CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2010	Dec. 31, 2009
Securities, available-for-sale, at fair value:
Fixed maturities (amortized cost, 2010 - $6,848,738; 2009 - $7,091,840)	$ 7,119,905	$ 7,251,574
Equity securities	3,126	2,891
Total investment portfolio	7,123,031	7,254,465
Cash and cash equivalents	2,166,101	1,185,739
Accrued investment income	68,427	79,828
Reinsurance recoverable on loss reserves (note 4)	299,239	332,227
Prepaid reinsurance premiums	2,924	3,554
Premium receivable	87,313	90,139
Home office and equipment, net	28,046	29,556
Deferred insurance policy acquisition costs	8,172	9,022
Income taxes recoverable (note 11)	0	275,187
Other assets	203,510	144,702
Total assets	9,986,763	9,404,419
Liabilities:
Loss reserves (note 12)	6,179,092	6,704,990
Premium deficiency reserve (note 13)	160,114	193,186
Unearned premiums	234,178	280,738
Senior notes (note 3)	377,271	377,098
Convertible senior notes (note 3)	345,000	0
Convertible junior debentures (note 3)	309,227	291,785
Other liabilities	398,436	254,041
Total liabilities	8,003,318	8,101,838
Contingencies (note 5)
Shareholders' equity: (note 14)
Common stock, $1 par value, shares authorized 460,000,000; shares issued, 2010 - 205,046,780; 2009 - 130,163,060; shares outstanding, 2010 - 200,449,588; 2009 - 125,101,057	205,047	130,163
Paid-in capital	1,135,572	443,294
Treasury stock (shares at cost, 2010 - 4,597,192; 2009 - 5,062,003)	(222,632)	(269,738)
Accumulated other comprehensive income, net of tax (note 9)	153,228	74,155
Retained earnings	712,230	924,707
Total shareholders' equity	1,983,445	1,302,581
Total liabilities and shareholders' equity	$ 9,986,763	$ 9,404,419

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2010	Sep. 30, 2009	Sep. 30, 2010	Sep. 30, 2009
Premiums written:
Direct	$ 294,478	$ 301,747	$ 883,922	$ 1,039,482
Assumed	764	826	2,340	3,133
Ceded	(16,260)	(24,319)	(55,876)	(86,465)
Net premiums written	278,982	278,254	830,386	956,150
Decrease in unearned premiums, net	17,514	15,261	47,236	40,327
Net premiums earned	296,496	293,515	877,622	996,477
Investment income, net of expenses	58,465	75,528	190,192	230,737
Realized investment gains, net	24,524	33,483	89,180	65,844
Total other-than-temporary impairment losses	0	0	(6,052)	(35,103)
Portion of losses recognized in other comprehensive income, before taxes	0	0	0	0
Net impairment losses recognized in earnings	0	0	(6,052)	(35,103)
Other revenue	2,840	10,811	8,508	45,048
Total revenue	382,325	413,337	1,159,450	1,303,003
Losses and expenses:
Losses incurred, net (note 12)	384,578	971,043	1,159,166	2,498,567
Change in premium deficiency reserve (note 13)	(8,887)	(19,346)	(33,072)	(246,533)
Amortization of deferred policy acquisition costs	1,750	2,013	5,243	5,974
Other underwriting and operating expenses, net	55,856	57,120	166,358	177,429
Reinsurance fee	0	0	0	26,407
Interest expense	26,702	20,586	72,819	68,442
Total losses and expenses	459,999	1,031,416	1,370,514	2,530,286
Loss before tax	(77,674)	(618,079)	(211,064)	(1,227,283)
Benefit from income taxes (note 11)	(26,146)	(100,311)	(33,996)	(185,120)
Net loss	$ (51,528)	$ (517,768)	$ (177,068)	$ (1,042,163)
Loss per share (note 6):
Basic (in dollars per share)	$ (0.26)	$ (4.17)	$ (1.05)	$ (8.39)
Diluted (in dollars per share)	$ (0.26)	$ (4.17)	$ (1.05)	$ (8.39)
Weighted average common shares outstanding - diluted (shares in thousands, note 6)	200,077,000	124,296,000	168,429,000	124,180,000

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (unaudited) (USD $) In Thousands	Total	Common stock	Paid-in capital	Treasury stock	Accumulated other comprehensive income (loss)	Retained earnings	Comprehensive income (loss)
Balance at Dec. 31, 2008		$ 130,119	$ 440,542	$ (276,873)	$ (106,789)	$ 2,247,234
Net loss		0	0	0	0	(1,322,277)	(1,322,277)
Change in unrealized investment gains and losses, net		0	0	0	154,358	0	154,358
Noncredit component of impairment losses, net		0	0	0	(1,764)	0	(1,764)
Common stock shares issued (note 14)		44	263	0	0	0
Reissuance of treasury stock, net		0	(11,613)	7,135	0	(545)
Equity compensation		0	14,102	0	0	0
Defined benefit plan adjustments, net		0	0	0	10,704	0	10,704
Unrealized foreign currency translation adjustment		0	0	0	17,646	0	17,646
Other		0	0	0	0	295
Comprehensive loss (note 9)		0	0	0	0	0	(1,141,333)
Balance at Dec. 31, 2009	1,302,581	130,163	443,294	(269,738)	74,155	924,707
Net loss	(177,068)	0	0	0	0	(177,068)	(177,068)
Change in unrealized investment gains and losses, net		0	0	0	74,931	0	74,931
Common stock shares issued (note 14)		74,884	697,492	0	0	0
Reissuance of treasury stock, net		0	(14,425)	47,106	0	(35,409)
Equity compensation		0	9,211	0	0	0
Unrealized foreign currency translation adjustment		0	0	0	4,142	0	4,142
Comprehensive loss (note 9)		0	0	0	0	0	(97,995)
Balance at Sep. 30, 2010	$ 1,983,445	$ 205,047	$ 1,135,572	$ (222,632)	$ 153,228	$ 712,230

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2010	Sep. 30, 2009
Cash flows from operating activities:
Net loss	$ (177,068)	$ (1,042,163)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Amortization of deferred insurance policy acquisition costs	5,243	5,974
Capitalized deferred insurance policy acquisition costs	(4,393)	(3,773)
Depreciation and amortization	43,569	47,376
Decrease in accrued investment income	11,401	409
Decrease (increase) in reinsurance recoverable on loss reserves	32,988	(151,412)
Decrease in prepaid reinsurance premiums	630	634
Decrease in premium receivable	2,826	2,289
(Increase) decrease in real estate acquired	(3,033)	29,595
(Decrease) increase in loss reserves	(525,898)	1,538,893
Decrease in premium deficiency reserve	(33,072)	(246,533)
Decrease in unearned premiums	(46,560)	(36,507)
Deferred tax (benefit) provision	(38,152)	146,217
Decrease in income taxes recoverable (current)	293,723	108,785
Realized investment gains, excluding impairment losses	(89,180)	(65,844)
Net investment impairment losses	6,052	35,103
Other	67,516	48,156
Net cash (used in) provided by operating activities	(453,408)	417,199
Cash flows from investing activities:
Purchase of fixed maturities	(3,544,492)	(3,362,579)
Purchase of equity securities	(82)	(1,356)
Proceeds from sale of equity securities	0	1,273
Proceeds from sale of fixed maturities	3,213,002	2,525,731
Proceeds from maturity of fixed maturities	644,028	411,445
Net increase in payable for securities	14,565	68,334
Net cash provided by (used in) investing activities	327,021	(357,152)
Cash flows from financing activities:
Net proceeds from convertible senior notes	334,373	0
Common stock shares issued	772,376	0
Repayment of note payable	0	(200,000)
Repayment of long-term debt	0	(87,659)
Net cash provided by (used in) financing activities	1,106,749	(287,659)
Net increase (decrease) in cash and cash equivalents	980,362	(227,612)
Cash and cash equivalents at beginning of period	1,185,739	1,097,334
Cash and cash equivalents at end of period	$ 2,166,101	$ 869,722

Basis of presentation	9 Months Ended
Basis of presentation	Sep. 30, 2010
Notes To Financial Statements [Abstract]
Basis of presentation	Note 1 - Basis of presentation The accompanying unaudited consolidated financial statements of MGIC Investment Corporation and its wholly-owned subsidiaries have been prepared in accordance with the instructions to Form 10-Q as prescribed by the Securities and Exchange Commission (“SEC”) for interim reporting and do not include all of the other information and disclosures required by accounting principles generally accepted in the United States of America. These statements should be read in conjunction with the consolidated financial statements and notes thereto for the year ended December 31, 2009 included in our Annual Report on Form 10-K. As used below, “we”, “our” and “us” refer to MGIC Investment Corporation’s consolidated operations or to MGIC Investment Corporation, as the context requires. In the opinion of management the accompanying financial statements include all adjustments, consisting primarily of normal recurring accruals, necessary to fairly state our financial position and results of operations for the periods indicated. The results of operations for the interim periods may not be indicative of the results that may be expected for the year ending December 31, 2010. Capital At September 30, 2010, Mortgage Guaranty Insurance Corporation’s (“MGIC”) policyholders position exceeded the required regulatory minimum by approximately $382 million, and we exceeded the required minimum by approximately $452 million on a combined statutory basis. (The combined figures give effect to reinsurance with subsidiaries of our holding company.) At September 30, 2010 MGIC’s risk-to-capital ratio was 17.7:1 and was 20.6:1 on a combined statutory basis. The insurance laws or regulations of 17 jurisdictions, including Wisconsin, require a mortgage insurer to maintain a minimum amount of statutory capital relative to the risk in force (or a similar measure) in order for the mortgage insurer to continue to write new business. We refer to these requirements as the risk-to-capital requirement. While formulations of minimum capital may vary in certain jurisdictions, the most common measure applied allows for a maximum permitted risk-to-capital ratio of 25 to 1. Based upon internal company estimates, MGIC’s risk-to-capital ratio over the next few years, after giving effect to any contribution to MGIC of the proceeds from our April 2010 common stock and convertible notes offerings beyond the contribution already made, could reach 40 to 1 or even higher under a stress loss scenario. For information regarding the assumptions underlying our forecasts, see our Risk Factor “We have reported net losses for the last three years, expect to continue to report annual net losses, and cannot assure you when we will return to profitability.” In December 2009, the Office of the Commissioner of Insurance for the State of Wisconsin (“OCI”) issued an order waiving, until December 31, 2011, its risk-to-capital requirement. MGIC has also applied for waivers in all other jurisdictions that have risk-to-capital requirements. MGIC has received waivers from some of these jurisdictions. These waivers expire at various times, with the earliest expiration being December 31, 2010. Some jurisdictions have denied the request and others may deny the request. The OCI and other insurance departments of other jurisdictions, in their sole discretion, may modify, terminate or extend their waivers. If the OCI or another insurance department modifies or terminates its waiver, or if it fails to renew its waiver after expiration, MGIC would be prevented from writing new business anywhere, in the case of the waiver from the OCI, or in the particular jurisdiction, in the case of the other waivers, if MGIC’s risk-to-capital ratio exceeds 25 to 1 unless MGIC obtained additional capital to enable it to comply with the risk-to-capital requirement. New insurance written in the jurisdictions that have risk-to-capital requirements represented approximately 50% of new insurance written in the first three quarters of 2010. If MGIC were prevented from writing new business in all jurisdictions, our insurance operations in MGIC would be in run-off (meaning no new loans would be insured but loans previously insured would continue to be covered, with premiums continuing to be received and losses continuing to be paid, on those loans) until MGIC either met the applicable risk-to-capital requirement or obtained a necessary waiver to allow it to once again write new business. We cannot assure you that the OCI or any other jurisdiction that has granted a waiver of its risk-to-capital requirements will not modify or revoke the waiver, that it will renew the waiver when it expires or that MGIC could obtain the additional capital necessary to comply with the risk-to-capital requirement. We have implemented a plan to write new mortgage insurance in MGIC Indemnity Corporation (“MIC”), a subsidiary of MGIC, in selected jurisdictions in order to address the likelihood that in the future MGIC will not meet the minimum regulatory capital requirements discussed above and may not be able to obtain appropriate waivers of these requirements in all jurisdictions in which minimum requirements are present. MIC has received the necessary approvals, including from the OCI, to write business in all of the jurisdictions in which MGIC would be prohibited from continuing to write new business in the event of MGIC’s failure to meet applicable regulatory capital requirements and obtain waivers of those requirements. In October 2009, we, MGIC and MIC entered into an agreement with Fannie Mae (the “Fannie Mae Agreement”) under which MGIC agreed to contribute $200 million to MIC (which MGIC has done) and Fannie Mae approved MIC as an eligible mortgage insurer through December 31, 2011 subject to the terms of the Fannie Mae Agreement. Under the Fannie Mae Agreement, MIC will be eligible to write mortgage insurance only in those jurisdictions (other than Wisconsin) in which MGIC cannot write new insurance due to MGIC’s failure to meet regulatory capital requirements and if MGIC fails to obtain relief from those requirements or a specified waiver of them. On February 11, 2010, Freddie Mac notified MGIC that it may utilize MIC to write new business in jurisdictions in which MGIC does not meet minimum regulatory capital requirements to write new business and does not obtain appropriate waivers of those requirements. This conditional approval to use MIC as a “Limited Insurer” (the “Freddie Mac Notification”) will expire December 31, 2012. This conditional approval includes terms substantially similar to those in the Fannie Mae Agreement. Under the Fannie Mae Agreement, Fannie Mae approved MIC as an eligible mortgage insurer only through December 31, 2011. Freddie Mac (together with Fannie Mae, referred to as “GSEs”) has approved MIC as a “Limited Insurer” only through December 31, 2012. Whether MIC will continue as an eligible mortgage insurer after these dates will be determined by the applicable GSE’s mortgage insurer eligibility requirements then in effect. Further, under the Fannie Mae Agreement and the Freddie Mac Notification, MGIC cannot capitalize MIC with more than the $200 million contribution already made without prior approval from each GSE, which limits the amount of business MIC can write. We believe that the amount of capital that MGIC has contributed to MIC will be sufficient to write business for the term of the Fannie Mae Agreement and the Freddie Mac Notification in the jurisdictions in which MIC is eligible to do so. Depending on the level of losses that MGIC experiences in the future, however, it is possible that regulatory action by one or more jurisdictions, including those that do not have specific regulatory capital requirements applicable to mortgage insurers, may prevent MGIC from continuing to write new insurance in some or all of the jurisdictions in which MIC is not eligible to write business. A failure to meet the specific minimum regulatory capital requirements to insure new business does not necessarily mean that MGIC does not have sufficient resources to pay claims on its insurance liabilities. While we believe that MGIC has sufficient claims paying resources to meet its claim obligations on its insurance in force, even in scenarios in which it fails to meet regulatory capital requirements, we cannot assure you that the events that led to MGIC failing to meet regulatory capital requirements would not also result in it not having sufficient claims paying resources. Furthermore, our estimates of MGIC’s claims paying resources and claim obligations are based on various assumptions. These assumptions include our anticipated rescission activity, future housing values and future unemployment rates. These assumptions are subject to inherent uncertainty and require judgment by management. Current conditions in the domestic economy make the assumptions about housing values and unemployment rates highly volatile in the sense that there is a wide range of reasonably possible outcomes. Our anticipated rescission activity is also subject to inherent uncertainty due to the difficulty of predicting the amount of claims that will be rescinded and the outcome of any dispute resolution proceedings related to rescissions that we make. Historically, rescissions of policies for which claims have been submitted to us were not a material portion of our claims resolved during a year. However, beginning in 2008, our rescissions of policies have materially mitigated our paid and incurred losses. In 2009, rescissions mitigated our paid losses by $1.2 billion and in the first nine months of 2010, rescissions mitigated our paid losses by $903 million (both of these figures include amounts that would have resulted in either a claim payment or been charged to a deductible under a bulk or pool policy, and may have been charged to a captive reinsurer). While we have a substantial pipeline of claims investigations that we expect will eventually result in future rescissions, we expect that rescissions will not continue to mitigate paid losses at the same level we have recently experienced. Our loss reserving methodology incorporates the effects rescission activity is expected to have on the losses we will pay on our delinquent inventory. A variance between ultimate actual rescission rates and these estimates, as a result of the outcome of claims investigations, litigation, settlements or other factors, could materially affect our losses. We estimate rescissions mitigated our incurred losses by approximately $2.5 billion in calendar year 2009, compared to a net $0.5 billion in the first three quarters of 2010, with all of the mitigation of incurred losses for 2010 being realized in the first quarter. Both of these figures include the benefit of claims not paid in the period as well as the impact of changes in our estimated expected rescission activity on our loss reserves in the period. Our loss reserves continue to be significantly mitigated by expected rescission activity. In recent quarters, between 25% and 30% of claims received in a quarter have been resolved by rescissions. At September 30, 2010, we had 223,373 loans in our primary delinquency inventory; the resolution of a significant portion of these loans will not involve paid claims. In addition, if MGIC’s right to rescind coverage is disputed, the outcome of the dispute ultimately would be determined by legal proceedings. Objections to rescission may be made several years after we have rescinded an insurance policy. Countrywide Home Loans, Inc. and an affiliate (“Countrywide”) have filed a lawsuit against MGIC alleging that MGIC has denied, and continues to deny, valid mortgage insurance claims. MGIC has filed an arbitration case against Countrywide regarding rescissions and Countrywide has responded seeking damages of at least $150 million, exclusive of interest and costs. For more information about this lawsuit and arbitration case, see Note 5. In the second quarter of 2010, we entered into a settlement agreement with a lender-customer regarding our rescission practices. Loans covered by this settlement agreement represented fewer than 10% of our policies in force as well as our delinquent inventory. Under this agreement, we waived certain of our rescission rights on loans subject to the agreement and the customer agreed to contribute to the cost of claims that we pay on these loans. The rescission rights we waived are for matters related to loan origination, which historically have been the basis of substantially all of our rescissions. In addition, under the agreement we reversed certain rescissions and the customer waived claims regarding certain other past rescissions. We continue to discuss with other lenders their objections to material rescissions and/or the possibility of entering into a settlement agreement. In addition to the proceedings involving Countrywide, we are involved in litigation and arbitration proceedings with respect to rescissions that we do not consider to be collectively material in amount. Reclassifications Certain reclassifications have been made in the accompanying financial statements to 2009 amounts to conform to 2010 presentation.

- Definition

Description containing the entire organization, consolidation and basis of presentation of financial statements disclosure. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements.

+ References+ Details

Debt	9 Months Ended
Debt	Sep. 30, 2010
Notes To Financial Statements [Abstract]
Debt	Note 3 – Debt Senior Notes At September 30, 2010 and December 31, 2009 we had outstanding $78.4 million, 5.625% Senior Notes due in September 2011 and $300 million, 5.375% Senior Notes due in November 2015. Covenants in the Senior Notes include the requirement that there be no liens on the stock of the designated subsidiaries unless the Senior Notes are equally and ratably secured; that there be no disposition of the stock of designated subsidiaries unless all of the stock is disposed of for consideration equal to the fair market value of the stock; and that we and the designated subsidiaries preserve our corporate existence, rights and franchises unless we or such subsidiary determines that such preservation is no longer necessary in the conduct of its business and that the loss thereof is not disadvantageous to the Senior Notes. A designated subsidiary is any of our consolidated subsidiaries which has shareholder’s equity of at least 15% of our consolidated shareholders equity. We were in compliance with all covenants at September 30, 2010. If we fail to meet any of the covenants of the Senior Notes discussed above; there is a failure to pay when due at maturity, or a default results in the acceleration of maturity of, any of our other debt in an aggregate amount of $40 million or more; or we fail to make a payment of principal of the Senior Notes when due or a payment of interest on the Senior Notes within thirty days after due and we are not successful in obtaining an agreement from holders of a majority of the applicable series of Senior Notes to change (or waive) the applicable requirement or payment default, then the holders of 25% or more of either series of our Senior Notes each would have the right to accelerate the maturity of that series. In addition, the Trustee of these two issues of Senior Notes could, independent of any action by holders of Senior Notes, accelerate the maturity of the Senior Notes. At September 30, 2010 and December 31, 2009, the fair value of the amount outstanding under our Senior Notes was $348.5 million and $293.2 million, respectively. The fair value was determined using publicly available trade information. Interest payments on the Senior Notes were $12.5 million and $16.3 million for the nine months ended September 30, 2010 and 2009, respectively. Convertible Senior Notes In April 2010 we completed the sale of $345 million principal amount of 5% Convertible Senior Notes due in 2017. We received net proceeds of approximately $334.4 million after deducting underwriting discount and offering expenses. Interest on the Convertible Senior Notes will be payable semi-annually in arrears on May 1 and November 1 of each year, beginning on November 1, 2010. We do not have the right to defer interest payments on the Convertible Senior Notes. The Convertible Senior Notes will mature on May 1, 2017, unless earlier converted by the holders or repurchased by us. Covenants in the Convertible Senior Notes include a requirement to notify holders in advance of certain events and that we and the designated subsidiaries (defined above) preserve our corporate existence, rights and franchises unless we or such subsidiary determines that such preservation is no longer necessary in the conduct of its business and that the loss thereof is not disadvantageous to the Convertible Senior Notes. If we fail to meet any of the covenants of the Convertible Senior Notes; there is a failure to pay when due at maturity, or a default results in the acceleration of maturity of, any of our other debt in an aggregate amount of $40 million or more; a final judgment for the payment of $40 million or more (excluding any amounts covered by insurance) is rendered against us or any of our subsidiaries which judgment is not discharged or stayed within certain time limits; or we fail to make a payment of principal of the Convertible Senior Notes when due or a payment of interest on the Convertible Senior Notes within thirty days after due and we are not successful in obtaining an agreement from holders of a majority of the Convertible Senior Notes to change (or waive) the applicable requirement or payment default, then the holders of 25% or more of the Convertible Senior Notes would have the right to accelerate the maturity of those notes. In addition, the Trustee of the Convertible Senior Notes could, independent of any action by holders, accelerate the maturity of the Convertible Senior Notes. The Convertible Senior Notes are convertible, at the holder's option, at an initial conversion rate, which is subject to adjustment, of 74.4186 shares per $1,000 principal amount at any time prior to the maturity date. This represents an initial conversion price of approximately $13.44 per share. The initial conversion price represents a 25% conversion premium based on the $10.75 per share price to the public in our concurrent common stock offering as discussed in Note 14. These Convertible Senior Notes will be equal in right of payment to our existing Senior Notes, discussed above, and will be senior in right of payment to our existing Convertible Junior Debentures, discussed below. Debt issuance costs will be amortized to interest expense over the contractual life of the Convertible Senior Notes. The provisions of the Convertible Senior Notes are complex. The description above is not intended to be complete in all respects. Moreover, that description is qualified in its entirety by the terms of the notes, which are contained in the Supplemental Indenture, dated as of April 26, 2010, between us and U.S. Bank National Association, as Trustee (the “Trustee”), and the Indenture dated as of October 15, 2000, between us and the Trustee. We intend to use the net proceeds from the offering to provide funds to repay at maturity or repurchase prior to maturity the $78.4 million outstanding principal amount of our 5.625% Senior Notes due in September 2011 and for our general corporate purposes, which may include improving liquidity by providing funds for debt service and increasing the capital of MGIC and other subsidiaries. At September 30, 2010, the fair value of the amount outstanding under our Convertible Senior Notes was $365.7 million. The fair value was determined using publicly available trade information. Convertible Junior Subordinated Debentures At September 30, 2010 and December 31, 2009 we had outstanding $389.5 million principal amount of 9% Convertible Junior Subordinated Debentures due in 2063 (the “debentures”). The debentures have an effective interest rate of 19% that reflects our non-convertible debt borrowing rate at the time of issuance. At September 30, 2010 and December 31, 2009 the amortized value of the principal amount of the debentures is reflected as a liability on our consolidated balance sheet of $309.2 million and $291.8 million, respectively, with the unamortized discount reflected in equity. At September 30, 2010 and December 31, 2009 we also had $57.5 million and $35.8 million, respectively, of deferred interest outstanding on the debentures which is included in other liabilities on the consolidated balance sheet. The debentures rank junior to all of our existing and future senior indebtedness. Interest on the debentures is payable semi-annually in arrears on April 1 and October 1 of each year. As long as no event of default with respect to the debentures has occurred and is continuing, we may defer interest, under an optional deferral provision, for one or more consecutive interest periods up to ten years without giving rise to an event of default. Deferred interest will accrue additional interest at the rate then applicable to the debentures. Violations of the covenants under the Indenture governing the debentures, including covenants to provide certain documents to the trustee, are not events of default under the Indenture and would not allow the acceleration of amounts that we owe under the debentures. Similarly, events of default under, or acceleration of, any of our other obligations, including those described above, would not allow the acceleration of amounts that we owe under the debentures. However, violations of the events of default under the Indenture, including a failure to pay principal when due under the debentures and certain events of bankruptcy, insolvency or receivership involving our holding company would allow acceleration of amounts that we owe under the debentures. Interest on the debentures that would have been payable on the scheduled interest payment dates of April 1, 2009, October 1, 2009 and April 1, 2010 had been deferred for up to 10 years past the scheduled payment date. During this deferral period the deferred interest continued to accrue and compound semi-annually to the extent permitted by applicable law at an annual rate of 9%. On October 1, 2010 we paid each of those deferred interest payments, including the compound interest on each. The interest payments, totaling approximately $57.5 million, were made from the net proceeds of our April 2010 common stock offering. We also paid the regular October 1, 2010 interest payment due on the debentures of approximately $17.5 million. We continue to have the right to defer interest that is payable on subsequent scheduled interest payment dates if we give the required 15 day notice. Any deferral of such interest would be on terms equivalent to those described above. When interest on the debentures is deferred, we are required, not later than a specified time, to use reasonable commercial efforts to begin selling qualifying securities to persons who are not our affiliates. The specified time is one business day after we pay interest on the debentures that was not deferred, or if earlier, the fifth anniversary of the scheduled interest payment date on which the deferral started. Qualifying securities are common stock, certain warrants and certain non-cumulative perpetual preferred stock. The requirement to use such efforts to sell such securities is called the Alternative Payment Mechanism. Although there was no requirement to begin the Alternative Payment Mechanism, with respect to the deferral of interest described above, the common shares issued in April 2010, discussed in Note 14, were qualifying securities. We had 180 days from the date of issuance of those shares to elect to use the proceeds to pay deferred interest and we elected to do so as described above. The net proceeds of Alternative Payment Mechanism sales are to be applied to the payment of deferred interest, including the compound portion. We cannot pay deferred interest other than from the net proceeds of Alternative Payment Mechanism sales, except at the final maturity of the debentures or at the tenth anniversary of the start of the interest deferral. The Alternative Payment Mechanism does not require us to sell common stock or warrants before the fifth anniversary of the interest payment date on which that deferral started if the net proceeds (counting any net proceeds of those securities previously sold under the Alternative Payment Mechanism) would exceed the 2% cap. The 2% cap is 2% of the average closing price of our common stock times the number of our outstanding shares of common stock. The average price is determined over a specified period ending before the issuance of the common stock or warrants being sold, and the number of outstanding shares is determined as of the date of our most recent publicly released financial statements. We are not required to issue under the Alternative Payment Mechanism a total of more than 10 million shares of common stock, including shares underlying qualifying warrants. In addition, we may not issue under the Alternative Payment Mechanism qualifying preferred stock if the total net proceeds of all issuances would exceed 25% of the aggregate principal amount of the debentures. The Alternative Payment Mechanism does not apply during any period between scheduled interest payment dates if there is a “market disruption event” that occurs over a specified portion of such period. Market disruption events include any material adverse change in domestic or international economic or financial conditions. The provisions of the Alternative Payment Mechanism are complex. The description above is not intended to be complete in all respects. Moreover, that description is qualified in its entirety by the terms of the debentures, which are contained in the Indenture, dated as of March 28, 2008, between us and U.S. Bank National Association, as trustee. We may redeem the debentures prior to April 6, 2013, in whole but not in part, only in the event of a specified tax or rating agency event, as defined in the Indenture. In any such event, the redemption price will be equal to the greater of (1) 100% of the principal amount of the debentures being redeemed and (2) the applicable make-whole amount, as defined in the Indenture, in each case plus any accrued but unpaid interest. On or after April 6, 2013, we may redeem the debentures in whole or in part from time to time, at our option, at a redemption price equal to 100% of the principal amount of the debentures being redeemed plus any accrued and unpaid interest if the closing sale price of our common stock exceeds 130% of the then prevailing conversion price of the debentures for at least 20 of the 30 trading days preceding notice of the redemption. We will not be able to redeem the debentures, other than in the event of a specified tax event or rating agency event, during an optional deferral period. The debentures are currently convertible, at the holder's option, at an initial conversion rate, which is subject to adjustment, of 74.0741 common shares per $1,000 principal amount of debentures at any time prior to the maturity date. This represents an initial conversion price of approximately $13.50 per share. If a holder elects to convert their debentures, deferred interest owed on the debentures being converted is also converted into shares of our common stock. The conversion rate for any deferred interest is based on the average price that our shares traded at during a 5-day period immediately prior to the election to convert. In 2009, we issued 44,316 shares of our common stock on conversion of $478,000 principal amount of our convertible debentures and related deferred interest. In lieu of issuing shares of common stock upon conversion of the debentures occurring after April 6, 2013, we may, at our option, make a cash payment to converting holders equal to the value of all or some of the shares of our common stock otherwise issuable upon conversion. The fair value of the debentures was approximately $402.2 million and $254.3 million, respectively, at September 30, 2010 and December 31, 2009, as determined using available pricing for these debentures or similar instruments.

Litigation and contingencies	9 Months Ended
Litigation and contingencies	Sep. 30, 2010
Notes To Financial Statements [Abstract]
Litigation and contingencies	Note 5 – Litigation and contingencies In addition to the matters described below, we are involved in other legal proceedings in the ordinary course of business. In our opinion, based on the facts known at this time, the ultimate resolution of these ordinary course legal proceedings will not have a material adverse effect on our financial position or results of operations. The assessment of materiality underlying this conclusion does not take account of whether the resolution of such proceedings would cause income from operations to become a loss from operations. Consumers are bringing a growing number of lawsuits against home mortgage lenders and settlement service providers. Seven mortgage insurers, including MGIC, have been involved in litigation alleging violations of the anti-referral fee provisions of the Real Estate Settlement Procedures Act, which is commonly known as RESPA, and the notice provisions of the Fair Credit Reporting Act, which is commonly known as FCRA. MGIC’s settlement of class action litigation against it under RESPA became final in October 2003. MGIC settled the named plaintiffs’ claims in litigation against it under FCRA in late December 2004 following denial of class certification in June 2004. Since December 2006, class action litigation was separately brought against a number of large lenders alleging that their captive mortgage reinsurance arrangements violated RESPA. While we are not a defendant in any of these cases, there can be no assurance that we will not be subject to future litigation under RESPA or FCRA or that the outcome of any such litigation would not have a material adverse effect on us. We are subject to comprehensive, detailed regulation by state insurance departments. These regulations are principally designed for the protection of our insured policyholders, rather than for the benefit of investors. Although their scope varies, state insurance laws generally grant broad supervisory powers to agencies or officials to examine insurance companies and enforce rules or exercise discretion affecting almost every significant aspect of the insurance business. Given the recent significant losses incurred by many insurers in the mortgage and financial guaranty industries, our insurance subsidiaries have been subject to heightened scrutiny by insurance regulators. State insurance regulatory authorities could take actions, including changes in capital requirements or termination of waivers of capital requirements, that could have a material adverse effect on us. In addition, the Dodd-Frank Act, the financial reform legislation that was passed in July 2010, establishes the Bureau of Consumer Financial Protection to regulate the offering and provision of consumer financial products or services under federal law. We are uncertain whether this Bureau will issue any rules or regulations that affect our business. Such rules and regulations could have a material adverse effect on us. In June 2005, in response to a letter from the New York Insurance Department, we provided information regarding captive mortgage reinsurance arrangements and other types of arrangements in which lenders receive compensation. In February 2006, the New York Insurance Department requested MGIC to review its premium rates in New York and to file adjusted rates based on recent years’ experience or to explain why such experience would not alter rates. In March 2006, MGIC advised the New York Insurance Department that it believes its premium rates are reasonable and that, given the nature of mortgage insurance risk, premium rates should not be determined only by the experience of recent years. In February 2006, in response to an administrative subpoena from the Minnesota Department of Commerce (the “MN Department”), which regulates insurance, we provided the MN Department with information about captive mortgage reinsurance and certain other matters. We subsequently provided additional information to the MN Department, and beginning in March 2008 the MN Department has sought additional information as well as answers to questions regarding captive mortgage reinsurance on several occasions. In addition, beginning in June 2008, we have received subpoenas from the Department of Housing and Urban Development, commonly referred to as HUD, seeking information about captive mortgage reinsurance similar to that requested by the MN Department, but not limited in scope to the state of Minnesota. Other insurance departments or other officials, including attorneys general, may also seek information about or investigate captive mortgage reinsurance. The anti-referral fee provisions of RESPA provide that HUD as well as the insurance commissioner or attorney general of any state may bring an action to enjoin violations of these provisions of RESPA. The insurance law provisions of many states prohibit paying for the referral of insurance business and provide various mechanisms to enforce this prohibition. While we believe our captive reinsurance arrangements are in conformity with applicable laws and regulations, it is not possible to predict the outcome of any such reviews or investigations nor is it possible to predict their effect on us or the mortgage insurance industry. Since October 2007 we have been involved in an investigation conducted by the Division of Enforcement of the SEC. The investigation has focused on disclosure and financial reporting by us and by a co-investor in 2007 regarding our respective investments in our C-BASS joint venture. We have provided documents to the SEC and a number of our executive officers, as well as other employees, have testified and we have had discussions with the SEC staff. This matter is ongoing and no assurance can be given that the SEC staff will not recommend an enforcement action against our company or one or more of our executive officers or other employees. Five previously-filed purported class action complaints filed against us and several of our executive officers were consolidated in March 2009 in the United States District Court for the Eastern District of Wisconsin and Fulton County Employees’ Retirement System was appointed as the lead plaintiff. The lead plaintiff filed a Consolidated Class Action Complaint (the “Complaint”) on June 22, 2009. Due in part to its length and structure, it is difficult to summarize briefly the allegations in the Complaint but it appears the allegations are that we and our officers named in the Complaint violated the federal securities laws by misrepresenting or failing to disclose material information about (i) loss development in our insurance in force, and (ii) C-BASS, including its liquidity. Our motion to dismiss the Complaint was granted on February 18, 2010. On March 18, 2010, plaintiffs filed a motion for leave to file an amended complaint. Attached to this motion was a proposed Amended Complaint (the “Amended Complaint”). The Amended Complaint alleges that we and two of our officers named in the Amended Complaint violated the federal securities laws by misrepresenting or failing to disclose material information about C-BASS, including its liquidity, and by failing to properly account for our investment in C-BASS. The Amended Complaint also names two officers of C-BASS with respect to the Amended Complaint’s allegations regarding C-BASS. The purported class period covered by the Amended Complaint begins on February 6, 2007 and ends on August 13, 2007. The Amended Complaint seeks damages based on purchases of our stock during this time period at prices that were allegedly inflated as a result of the purported violations of federal securities laws. On April 12, 2010, we filed a motion in opposition to Plaintiff’s motion for leave to amend its complaint. We are unable to predict the outcome of these consolidated cases or estimate our associated expenses or possible losses. Other lawsuits alleging violations of the securities laws could be brought against us. Several law firms have issued press releases to the effect that they are investigating us, including whether the fiduciaries of our 401(k) plan breached their fiduciary duties regarding the plan’s investment in or holding of our common stock or whether we breached other legal or fiduciary obligations to our shareholders. We intend to defend vigorously any proceedings that may result from these investigations. With limited exceptions, our bylaws provide that our officers and 401(k) plan fiduciaries are entitled to indemnification from us for claims against them. On December 17, 2009, Countrywide filed a complaint for declaratory relief in the Superior Court of the State of California in San Francisco (the “California State Court”) against MGIC. This complaint alleges that MGIC has denied, and continues to deny, valid mortgage insurance claims submitted by Countrywide and says it seeks declaratory relief regarding the proper interpretation of the flow insurance policies at issue, which are in the same form as the flow policies that we use with all of our customers. On January 19, 2010, we removed this case to the United States District Court for the Northern District of California (the “District Court”). On March 30, 2010, the District Court ordered the case remanded to the California State Court. We have appealed this decision to the United States Court of Appeals for the Ninth Circuit (the “Court of Appeals”) and asked the Court of Appeals to vacate the remand and stay proceedings in the District Court. On May 17, 2010, the Court of Appeals denied a stay of the District Court’s remand order. On May 28, 2010, Countrywide filed an amended complaint substantially similar to the original complaint in the California State Court. On July 2, 2010, we filed a petition in the California State Court to compel arbitration and stay the litigation in that court. On August 26, 2010, Countrywide filed an opposition to our petition. Countrywide’s opposition states that there are thousands of loans for which it disputes MGIC’s interpretation of the flow insurance policies at issue. On September 16, 2010, we filed a reply to Countrywide’s opposition. On October 1, 2010, the California State Court stayed the litigation in that court pending a final ruling on our appeal. In connection with the Countrywide dispute discussed above, on February 24, 2010, we commenced an arbitration action against Countrywide seeking a determination that MGIC was entitled to deny and/or rescind coverage on the loans involved in the arbitration action, which were insured through the flow channel and numbered more than 1,400 loans as of the filing of the action. Since we commenced the arbitration action, we have rescinded insurance coverage on more than one thousand additional Countrywide loans insured through the flow channel. On March 16, 2010, Countrywide filed a response to our arbitration action objecting to the arbitrator’s jurisdiction in view of the case initiated by Countrywide in the California State Court and asserting various defenses to the relief sought by MGIC in the arbitration. The response also seeks damages of at least $150 million, exclusive of interest and costs, as a result of purported breaches of flow insurance policies issued by MGIC and additional damages, including exemplary damages, on account of MGIC’s purported breach of an implied covenant of good faith and fair dealing. In October 2010, Countrywide informed us that it intended to amend its response to include loans insured through the bulk channel, which we believe will add more than one thousand loans to the arbitration action. As a result of additional flow rescissions since Countrywide’s arbitration response and its statement regarding inclusion of bulk loans in the arbitration, the damages Countrywide is seeking may increase materially. At September 30, 2010, Countrywide loans represent approximately 24% of our primary delinquency inventory. We intend to defend MGIC against Countrywide’s complaint and arbitration response, and to pursue MGIC’s claims in the arbitration, vigorously. However, we are unable to predict the outcome of these proceedings or their effect on us. In addition to the rescissions at issue with Countrywide, we have a substantial pipeline of claims investigations (including investigations involving loans related to Countrywide) that we expect will eventually result in future rescissions. In the second quarter of 2010, we entered into a settlement agreement with a lender-customer regarding our rescission practices. See Note 1, above, for information about the settlement agreement. We provide an outsourced underwriting service to our customers known as contract underwriting. Under our contract underwriting agreements, we may be required to provide certain remedies to our customers if certain standards relating to the quality of our underwriting work are not met. We have an established reserve for such obligations. The cost of remedies provided by us to customers for failing to meet these standards has not been material to our financial position or results of operations for the nine months ended September 30, 2010 and 2009. A generally positive economic environment for residential real estate that continued until approximately 2007 may have mitigated the effect of some of these costs, and claims for remedies may be submitted a number of years after the underwriting work was performed. A material portion of our new insurance written through the flow channel in recent years, including for 2006 and 2007, involved loans for which we provided contract underwriting services. We believe the rescission of mortgage insurance coverage on loans for which we provided contract underwriting services may make a claim for a contract underwriting remedy more likely to occur. Beginning in the second half 2009, we experienced an increase in claims for contract underwriting remedies, which continued into 2010. See note 11 – “Income taxes” for a description of federal income tax contingencies.

Investments

9 Months Ended

Sep. 30, 2010

Notes To Financial Statements [Abstract]

Investments

Note 7 – Investments

The amortized cost, gross unrealized gains and losses and fair value of the investment portfolio at September 30, 2010 and December 31, 2009 are shown below. Debt securities consist of fixed maturities and short-term investments.

September 30, 2010	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)			Fair Value
	(In thousands of dollars)
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	1,174,828	$	27,139	$	(100	)	$	1,201,867
Obligations of U.S. states and political subdivisions		3,357,532		172,171		(16,681	)		3,513,022
Corporate debt securities		2,127,325		85,527		(4,436	)		2,208,416
Residential mortgage-backed securities		55,603		3,672		-			59,275
Debt securities issued by foreign sovereign governments		133,450		4,152		(277	)		137,325
Total debt securities	$	6,848,738	$	292,661	$	(21,494	)	$	7,119,905
Equity securities		2,975		151		-			3,126

Total investment portfolio	$	6,851,713	$	292,812	$	(21,494	)	$	7,123,031

December 31, 2009	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)			Fair Value
	(In thousands of dollars)
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	736,668	$	4,877	$	(6,357	)	$	735,188
Obligations of U.S. states and political subdivisions		4,607,936		187,540		(59,875	)		4,735,601
Corporate debt securities		1,532,571		40,328		(9,158	)		1,563,741
Residential mortgage-backed securities		102,062		3,976		(1,986	)		104,052
Debt securities issued by foreign sovereign governments		112,603		1,447		(1,058	)		112,992
Total debt securities	$	7,091,840	$	238,168	$	(78,434	)	$	7,251,574
Equity securities		2,892		3		(4	)		2,891

Total investment portfolio	$	7,094,732	$	238,171	$	(78,438	)	$	7,254,465

(1) At September 30, 2010 and December 31, 2009, gross unrealized losses for residential mortgage-backed securities include $0 million and $1.8 million, respectively, in other-than-temporary impairment losses recorded in other comprehensive income, since the adoption of new guidance on other-than-temporary impairments.

The amortized cost and fair values of debt securities at September 30, 2010, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most auction rate and mortgage-backed securities provide for periodic payments throughout their lives, they are listed below in separate categories.

September 30, 2010	Amortized Cost		Fair Value
	(In thousands of dollars)

Due in one year or less	$	61,221	$	61,939
Due after one year through five years		3,439,181		3,533,562
Due after five years through ten years		1,256,435		1,328,778
Due after ten years		1,634,673		1,752,475

	$	6,391,510	$	6,676,754

Residential mortgage-backed securities		55,603		59,275
Auction rate securities (1)		401,625		383,876

Total at September 30, 2010	$	6,848,738	$	7,119,905

(1) At September 30, 2010, approximately 98% of auction rate securities had a contractual maturity greater than 10 years.

At September 30, 2010 and December 31, 2009, the investment portfolio had gross unrealized losses of $21.5 million and $78.4 million, respectively. For those securities in an unrealized loss position, the length of time the securities were in such a position, as measured by their month-end fair values, is as follows:

	Less Than 12 Months				12 Months or Greater				Total
September 30, 2010	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In thousands of dollars)
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	44,166	$	100	$	-	$	-	$	44,166	$	100
Obligations of U.S. states and political subdivisions		146,297		423		414,163		16,258		560,460		16,681
Corporate debt securities		141,661		576		80,769		3,860		222,430		4,436
Residential mortgage- backed securities		-		-		-		-		-		-
Debt issued by foreign sovereign governments		23,164		88		4,398		189		27,562		277
Equity securities		6		-		-		-		6		-
Total investment portfolio	$	355,294	$	1,187	$	499,330	$	20,307	$	854,624	$	21,494

	Less Than 12 Months				12 Months or Greater				Total
December 31, 2009	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In thousands of dollars)
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	434,362	$	6,357	$	-	$	-	$	434,362	$	6,357
Obligations of U.S. states and political subdivisions		926,860		29,390		398,859		30,485		1,325,719		59,875
Corporate debt securities		453,804		9,158		-		-		453,804		9,158
Residential mortgage- backed securities		8,743		1,764		870		222		9,613		1,986
Debt issued by foreign sovereign governments		56,122		1,058		-		-		56,122		1,058
Equity securities		2,398		4		-		-		2,398		4
Total investment portfolio	$	1,882,289	$	47,731	$	399,729	$	30,707	$	2,282,018	$	78,438

There were 135 securities in an unrealized loss position at September 30, 2010. The unrealized losses in all categories of our investments were primarily caused by the difference in interest rates at September 30, 2010 and December 31, 2009, compared to the interest rates at the time of purchase as well as the illiquidity premium applied in our auction rate securities discounted cash flow model. All of the securities in an unrealized loss position greater than 12 months at September 30, 2010 had a fair value greater than 80% of amortized cost.

Under the current guidance a debt security impairment is deemed other than temporary if we either intend to sell the security, or it is more likely than not that we will be required to sell the security before recovery or we do not expect to collect cash flows sufficient to recover the amortized cost basis of the security. During the third quarter and first nine months of 2010 we recognized other-than-temporary impairments (“OTTI”) in earnings of $0 and $6.1 million, respectively, compared to $0 and $35.1 million, respectively, during the third quarter and first nine months of 2009. Our OTTI during these periods in 2010 and 2009 was primarily related to securities for which we had the intent to sell.

The following table provides a rollforward of the amount related to credit losses recognized in earnings for which a portion of an OTTI was recognized in accumulated other comprehensive income (loss) for the three and nine months ended September 30, 2010.

	Three months ended		Nine months ended
	September 30, 2010
	(In thousands of dollars)

Beginning balance	$	-	$	1,021
Addition for the amount related to the credit loss for which an OTTI was not previously recognized		-		-
Additional increases to the amount related to the credit loss for which an OTTI was previously recognized		-		-
Reductions for securities sold during the period (realized)		-		(1,021	)
Ending balance	$	-	$	-

We held $383.9 million in auction rate securities (ARS) backed by student loans at September 30, 2010. ARS are intended to behave like short-term debt instruments because their interest rates are reset periodically through an auction process, most commonly at intervals of 7, 28 and 35 days. The same auction process has historically provided a means by which we may rollover the investment or sell these securities at par in order to provide us with liquidity as needed. The ARS we hold are collateralized by portfolios of student loans, substantially all of which are ultimately 97% guaranteed by the United States Department of Education. At September 30, 2010, approximately 91% of our ARS portfolio was AAA/Aaa-rated by one or more of the following major rating agencies: Moody’s, Standard & Poor’s and Fitch Ratings.

In mid-February 2008, auctions began to fail due to insufficient buyers, as the amount of securities submitted for sale in auctions exceeded the aggregate amount of the bids. For each failed auction, the interest rate on the security moves to a maximum rate specified for each security, and generally resets at a level higher than specified short-term interest rate benchmarks. At September 30, 2010, our entire ARS portfolio, consisting of 36 investments, was subject to failed auctions, however, from the period when the auctions began to fail through September 30, 2010, $138.9 million in par value of ARS was either sold or called, with the average amount we received being 98% of par. To date, we have collected all interest due on our ARS.

As a result of the persistent failed auctions, and the uncertainty of when these investments could be liquidated at par, the investment principal associated with failed auctions will not be accessible until successful auctions occur, a buyer is found outside of the auction process, the issuers establish a different form of financing to replace these securities, or final payments come due according to the contractual maturities of the debt issues.

The net realized investment gains (losses) and OTTI on the investment portfolio are as follows:

		Three months ended				Nine months ended
		September 30,				September 30,
		2010		2009		2010		2009
	(In thousands of dollars)
Net realized investment gains (losses) and OTTI on investments:
Fixed maturities		$	24,503	$	33,074	$	82,819	$	30,035
Equity securities			15		40		72		181
Other			6		369		237		525

		$	24,524	$	33,483	$	83,128	$	30,741

		Three months ended						Nine months ended
		September 30,						September 30,
		2010			2009			2010			2009
	(In thousands of dollars)
Net realized investment gains (losses) and OTTI on investments:
Gains on sales		$	26,305		$	36,601		$	98,893		$	90,532
Losses on sales			(1,781	)		(3,118	)		(9,713	)		(24,688	)
Impairment losses			-			-			(6,052	)		(35,103	)

		$	24,524		$	33,483		$	83,128		$	30,741

The net realized gains on investments during 2010 and 2009 primarily resulted from sales of tax-exempt municipal securities. Such sales were made to reduce the proportion of our investment portfolio held in tax-exempt municipal securities and to increase the proportion held in taxable securities principally since the tax benefits of holding tax exempt municipal securities are no longer available based on our recent net operating losses and to shorten the duration of the portfolio to provide cash to meet our anticipated claim payment obligations.

- Definition

This item represents the entire disclosure related to Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References+ Details

Fair value measurements

9 Months Ended

Sep. 30, 2010

Notes To Financial Statements [Abstract]

Fair value measurements

Note 8 – Fair value measurements

Fair value measurements for items measured at fair value included the following as of September 30, 2010 and December 31, 2009:

	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands of dollars)
September 30, 2010
Assets
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	1,201,867	$	1,201,867	$	-	$	-
Obligations of U.S. states and political subdivisions		3,513,022		-		3,201,326		311,696
Corporate debt securities		2,208,416		2,618		2,125,556		80,242
Residential mortgage-backed securities		59,275		-		59,275		-
Debt securities issued by foreign sovereign governments		137,325		127,905		9,420		-
Total debt securities		7,119,905		1,332,390		5,395,577		391,938
Equity securities		3,126		2,805		-		321

Total investments	$	7,123,031	$	1,335,195	$	5,395,577	$	392,259

Real estate acquired (1)	$	6,863	$	-	$	-	$	6,863
December 31, 2009
Assets
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	735,188	$	735,188	$	-	$	-
Obligations of U.S. states and political subdivisions		4,735,601		-		4,365,260		370,341
Corporate debt securities		1,563,741		2,559		1,431,844		129,338
Residential mortgage-backed securities		104,052		23,613		80,439		-
Debt securities issued by foreign sovereign governments		112,992		101,983		11,009		-
Total debt securities		7,251,574		863,343		5,888,552		499,679
Equity securities		2,891		2,570		-		321

Total investments	$	7,254,465	$	865,913	$	5,888,552	$	500,000

Real estate acquired (1)	$	3,830	$	-	$	-	$	3,830

(1)	Real estate acquired through claim settlement, which is held for sale, is reported in Other Assets on the consolidated balance sheet.

There were no transfers of securities between Level 1 and Level 2 during the first nine months of 2010.

For assets and liabilities measured at fair value using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances for the three and nine months ended September 30, 2010 and 2009 is as follows:

	Obligations of U.S. States and Political Subdivisions			Corporate Debt Securities			Equity Securities		Total Investments			Real Estate Acquired
	(in thousands of dollars)
Balance at June 30, 2010	$	321,050		$	94,564		$	321	$	415,935		$	5,671
Total realized/unrealized gains (losses):
Included in earnings and reported as realized investment losses, net		-			(1,057	)		-		(1,057	)		-
Included in earnings and reported as losses incurred, net		-			-			-		-			(701	)
Included in other comprehensive income		3,504			2,528			-		6,032			-
Purchases, issuances and settlements		(12,858	)		(15,793	)		-		(28,651	)		1,893
Transfers in and/or out of Level 3		-			-			-		-			-

Balance at September 30, 2010	$	311,696		$	80,242		$	321	$	392,259		$	6,863

Amount of total losses included in earnings for the three months ended September 30, 2010 attributable to the change in unrealized losses on assets still held at September 30, 2010	$	-		$	-		$	-	$	-		$	-

	Obligations of U.S. States and Political Subdivisions			Corporate Debt Securities			Equity Securities		Total Investments			Real Estate Acquired
	(in thousands of dollars)
Balance at December 31, 2009	$	370,341		$	129,338		$	321	$	500,000		$	3,830
Total realized/unrealized gains (losses):
Included in earnings and reported as realized investment losses, net		-			(2,455	)		-		(2,455	)		-
Included in earnings and reported as losses incurred, net		-			-			-		-			(1,635	)
Included in other comprehensive income		3,547			2,854			-		6,401			-
Purchases, issuances and settlements		(62,192	)		(49,495	)		-		(111,687	)		4,668
Transfers in and/or out of Level 3		-			-			-		-			-

Balance at September 30, 2010	$	311,696		$	80,242		$	321	$	392,259		$	6,863


Amount of total losses included in earnings for the nine months ended September 30, 2010 attributable to the change in unrealized losses on assets still held at September 30, 2010	$	-		$	-		$	-	$	-		$	-

	Obligations of U.S. States and Political Subdivisions			Corporate Debt Securities			Equity Securities		Total Investments			Real Estate Acquired
	(in thousand of dollars)
Balance at June 30, 2009	$	386,338		$	134,070		$	321	$	520,729		$	7,858
Total realized/unrealized gains (losses):
Included in earnings and reported as losses incurred, net		-			-			-		-			585
Included in other comprehensive income		(5,674	)		(2,038	)		-		(7,712	)		-
Purchases, issuances and settlements		(2,163	)		(200	)		-		(2,363	)		(5,180	)
Transfers in and/or out of Level 3		-			-			-		-			-

Balance at September 30, 2009	$	378,501		$	131,832		$	321	$	510,654		$	3,263


Amount of total losses included in earnings for the three months ended September 30, 2009 attributable to the change in unrealized losses on assets still held at September 30, 2009	$	-		$	-		$	-	$	-		$	-

	Obligations of U.S. States and Political Subdivisions			Corporate Debt Securities			Equity Securities		Total Investments			Real Estate Acquired
	(in thousands of dollars)
Balance at December 31, 2008	$	395,388		$	150,241		$	321	$	545,950		$	32,858
Total realized/unrealized losses:
Included in earnings and reported as realized investment losses, net		-			(10,107	)		-		(10,107	)		-
Included in earnings and reported as losses incurred, net		-			-			-		-			(1,304	)
Included in other comprehensive income		(11,777	)		(3,467	)		-		(15,244	)		-
Purchases, issuances and settlements		(5,110	)		(4,835	)		-		(9,945	)		(28,291	)
Transfers in and/or out of Level 3		-			-			-		-			-

Balance at September 30, 2009	$	378,501		$	131,832		$	321	$	510,654		$	3,263

Amount of total losses included in earnings for the nine months ended September 30, 2009 attributable to the change in unrealized losses on assets still held at September 30, 2009	$	-		$	-		$	-	$	-		$	-

Additional fair value disclosures related to our investment portfolio are included in Note 7. Fair value disclosures related to our debt are included in Note 3.

- Definition

This element represents the disclosure related to the fair value measurement of assets and liabilities which includes [financial] instruments measured at fair value that are classified in stockholders' equity. Such assets and liabilities may be measured on a recurring or nonrecurring basis. The disclosures which may be required or desired include: (1) for assets and liabilities measured on a recurring basis, disclosure may include: (a) the fair value measurements at the reporting date; (b) the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3); (c) for fair value measurements using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (i) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (ii) purchases, sales, issuances, and settlements (net); (iii) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs); (d) the amount of the total gains or losses for the period in subparagraph (c) (i) above included in earnings (or changes in net assets) that are attributable to the change in unrealized gains or losses relating to those assets and liabilities still held at the reporting date and a description of where those unrealized gains or losses are reported in the statement of income (or activities); (e) the valuation technique(s) used to measure fair value and a discussion of changes in valuation techniques, if any, during the period and (2) for assets and liabilities that are measured at fair value on a nonrecurring basis (for example, impaired assets) disclosure may include, in addition to (a) above: (a) the reasons for the fair value measurements recorded; (b) the same as (b) above; (c) for fair value measurements using significant unobservable inputs (Level 3), a description of the inputs and the information used to develop the inputs; and (d) the valuation technique(s) used to measure fair value and a discussion of changes, if any, in the valuation technique(s) used to measure similar assets and/or liabilities in prior periods.

+ References+ Details

Loss Reserves

9 Months Ended

Sep. 30, 2010

Notes To Financial Statements [Abstract]

Loss Reserves

Note 12 – Loss Reserves

Our loss estimates are established based upon historical experience. Losses incurred for the third quarter of 2010 significantly decreased compared to the third quarter of 2009 primarily due to the decrease in the primary default inventory, compared to an increase in 2009. The primary default inventory decreased by 5,082 delinquencies in the third quarter of 2010, compared to an increase of 23,373 in the third quarter of 2009. The estimated severity decreased in the third quarter of 2010 and remained relatively stable in the comparable period of 2009. The estimated claim rate was relatively flat in the third quarter of 2010 and 2009.

Losses incurred for the first nine months of 2010 significantly decreased compared to the first nine months of 2009 primarily due to the decrease in the primary default inventory, compared to an increase in 2009. The primary default inventory decreased by 27,067 delinquencies in the first nine months of 2010, compared to an increase of 53,422 in the first nine months of 2009. The estimated severity decreased in the first nine months of 2010 and increased slightly in the comparable period of 2009. The estimated claim rate increased slightly in the first nine months of 2010 and was relatively flat in the comparable period of 2009.

The decrease in the primary default inventory experienced during the first nine months of 2010 was generally across all markets and all book years. However the number of consecutive months a loan remains in the primary default inventory (the age of the item in default) continues to increase, as shown in the table below. Historically as a default ages it becomes more likely to result in a claim. The impact of the decrease in the primary default inventory and estimated severity on losses incurred in the first nine months of 2010 was partially offset by the impact of the increased age of the primary default inventory.

Aging of the Primary Default Inventory

	Q3 2010				Q2 2010				Q1 2010				Q4 2009				Q3 2009				Q2 2009

Consecutive months in the default inventory
3 months or less		39,516	18	%		35,838	16	%		36,256	15	%		48,252	19	%		53,615	23	%		50,297	24	%
4 - 11 months		60,472	27	%		71,089	31	%		90,816	38	%		98,210	39	%		97,435	41	%		93,704	44	%
12 months or more		123,385	55	%		121,528	53	%		114,172	47	%		103,978	42	%		84,560	36	%		68,236	32	%

Total primary default inventory		223,373	100	%		228,455	100	%		241,244	100	%		250,440	100	%		235,610	100	%		212,237	100	%

Loans in default in our claims received inventory		21,306	10	%		19,724	9	%		17,384	7	%		16,389	7	%		16,802	7	%		15,337	7	%

The length of time a loan is in the default inventory can differ from the number of payments that the borrower has not made or is considered delinquent. These differences typically result from a borrower making monthly payments that do not result in the loan becoming fully current. The number of payments that a borrower is delinquent is shown in the table below.

Number of Payments Delinquent

	Q3 2010				Q2 2010				Q1 2010				Q4 2009				Q3 2009				Q2 2009


3 payments or less		52,056	23	%		49,308	22	%		50,045	21	%		60,970	24	%		62,304	26	%		59,549	28	%
4 - 11 payments		70,681	32	%		80,224	35	%		98,753	41	%		105,208	42	%		101,076	43	%		93,997	44	%
12 payments or more		100,636	45	%		98,923	43	%		92,446	38	%		84,262	34	%		72,230	31	%		58,691	28	%

Total primary default inventory		223,373	100	%		228,455	100	%		241,244	100	%		250,440	100	%		235,610	100	%		212,237	100	%

Before paying a claim, we can review the loan file to determine whether we are required, under the applicable insurance policy, to pay the claim or whether we are entitled to reduce the amount of the claim. For example, all of our insurance policies provide that we can reduce or deny a claim if the servicer did not comply with its obligation to mitigate our loss by performing reasonable loss mitigation efforts or diligently pursuing a foreclosure or bankruptcy relief in a timely manner. We also do not cover losses resulting from property damage that has not been repaired. We are currently reviewing the loan files for the majority of the claims submitted to us.

In addition, subject to rescission caps in certain of our Wall Street bulk transactions, all of our insurance policies allow us to rescind coverage under certain circumstances. Because we can review the loan origination documents and information as part of our normal processing when a claim is submitted to us, rescissions occur on a loan by loan basis most often after we have received a claim. Historically, claim rescissions and denials, which we collectively refer to as rescissions, were not a material portion of our claims resolved during a year. However, beginning in 2008 our rescissions of policies have materially mitigated our paid and incurred losses. While we have a substantial pipeline of claims investigations that we expect will eventually result in future rescissions, we expect that rescissions will not continue to mitigate paid and incurred losses at the same level we have recently experienced. In addition, if an insured disputes our right to rescind coverage, the outcome of the dispute ultimately would be determined by legal proceedings. Rescissions mitigated our paid losses by approximately $263 million and $903 million, respectively, in the third quarter and first nine months of 2010, compared to approximately $390 million and $839 million, respectively, in the third quarter and first nine months of 2009. These figures include amounts that would have resulted in either a claim payment or been charged to a deductible under a bulk or pool policy, and may have been charged to a captive reinsurer. In the first nine months of 2010, $202 million, of the $903 million mitigated paid losses, would have been applied to a deductible had the policy not been rescinded. In the first nine months of 2009, $196 million, of the $839 million mitigated paid losses, would have been applied to a deductible. The amounts that would have been applied to a deductible do not take into account previous rescissions that may have been applied to a deductible.

In addition, our loss reserving methodology incorporates the effect that rescission activity is expected to have on the losses we will pay on our delinquent inventory. We do not utilize an explicit rescission rate in our reserving methodology, but rather our reserving methodology incorporates the effects rescission activity has had on our historical claim rate and claim severities. A variance between ultimate actual rescission rates and these estimates could materially affect our losses incurred. Our estimation process does not include a direct correlation between claim rates and severities to projected rescission activity or other economic conditions such as changes in unemployment rates, interest rates or housing values. Our experience is that analysis of that nature would not produce reliable results, as the change in one condition cannot be isolated to determine its sole effect on our ultimate paid losses as our ultimate paid losses are also influenced at the same time by other economic conditions.

Based upon the increase in rescission activity during 2008 and 2009, the effects rescissions had on our losses incurred became material. We estimate that rescissions mitigated our incurred losses by a net $0.5 billion in the first three quarters of 2010, with all of the mitigation of incurred losses for 2010 being realized in the first quarter, compared to approximately $1.8 billion and $0.8 billion for the first nine months and third quarter, respectively, in 2009.

The $1.8 billion mitigation of incurred losses during the first nine months of 2009 represents both the claims not paid in the period due to rescissions, as well as an increasing expected rescission rate for loans in the default inventory. Even though rescissions mitigated our paid losses by a larger amount for the first nine months of 2010 as compared to the same period in 2009, the mitigation of incurred losses declined to $0.5 billion for the first nine months of 2010. This decrease was caused by the expected rescission rate for loans in our default inventory remaining relatively flat during the first nine months of 2010 compared to a significantly increasing expected rescission rate during the same period in 2009.

At September 30, 2010, our loss reserves continued to be significantly impacted by expected rescission activity. We expect that the reduction of our loss reserves due to rescissions will continue to decline because our recent experience indicates new notices in our default inventory have a lower likelihood of being rescinded than those already in the inventory due to their product mix, geographic location and vintage.

The liability associated with our estimate of premiums to be refunded on expected future rescissions is accrued for separately. At September 30, 2010 and December 31, 2009 the estimate of this liability totaled $136 million and $88 million, respectively. Separate components of this liability are included in “Other liabilities” and “Premium deficiency reserve” on our consolidated balance sheet. Changes in the liability affect premiums written and earned.

If the insured disputes our right to rescind coverage, the outcome of the dispute ultimately would be determined by legal proceedings. Objections to rescission may be made several years after we have rescinded an insurance policy. Countrywide has filed a lawsuit against MGIC alleging that MGIC has denied, and continues to deny, valid mortgage insurance claims. We have filed an arbitration case against Countrywide regarding rescissions and Countrywide has responded seeking damages of at least $150 million, exclusive of interests and costs. For more information about this lawsuit and arbitration case, see Note 5 – “Litigation and contingencies.”

In the second quarter of 2010, we entered into a settlement agreement with a lender-customer regarding our rescission practices. Loans covered by this settlement agreement represented fewer than 10% of our policies in force as well as our delinquent inventory. Under this agreement, we waived certain of our rescission rights on loans subject to the agreement and the customer agreed to contribute to the cost of claims that we pay on those loans. The rescission rights we waived are for matters related to loan origination, which historically have been the basis for substantially all of our rescissions. In addition, under the agreement we reversed certain rescissions and the customer waived claims regarding certain other past rescissions. We continue to discuss with other lenders their objections to material rescissions and/or the possibility of entering into a settlement agreement. In addition to the proceedings involving Countrywide, we are involved in litigation and arbitration proceedings with respect to rescissions that we do not consider to be collectively material in amount.

Information regarding the ever-to-date rescission rates by the quarter in which the claim was received appears in the table below. No information is presented for claims received in the most recent two quarters to allow sufficient time for a substantial percentage of the claims received in those two quarters to reach resolution.

As of September 30, 2010

Ever to Date Rescission Rates on Primary Claims Received

(based on count)

Quarter in Which the Claim was Received		ETD Rescission Rate (1)			ETD Claims Resolution Percentage (2)

	Q1 2009		28.6	%		99.9	%
	Q2 2009		28.2	%		99.8	%
	Q3 2009		27.4	%		99.4	%
	Q4 2009		23.2	%		97.4	%
	Q1 2010		17.8	%		90.4	%

(1) This percentage is claims received during the quarter shown that have been rescinded as of our most recently completed quarter divided by the total claims received during the quarter shown.

(2) This percentage is claims received during the quarter shown that have been resolved as of our most recently completed quarter divided by the total claims received during the quarter shown. Claims resolved principally consist of claims paid plus claims for which we have informed the insured of our decision not to pay the claim. Although our decision to not pay a claim is made after we have given the insured an opportunity to dispute the facts underlying our decision to not pay the claim, these decisions are sometimes reversed after further discussion with the insured.

A rollforward of our primary default inventory for the three and nine months ended September 30, 2010 and 2009 appears in the table below. The information concerning new notices and cures is compiled from monthly reports received from loan servicers. The level of new notice and cure activity reported in a particular month can be influenced by, among other things, the date on which a servicer generates its report and by transfers of servicing between loan servicers.

	Three months ended September 30,						Nine months ended September 30,
	2010			2009			2010			2009

Default inventory at beginning of period		228,455			212,237			250,440			182,188
Plus: New Notices		53,134			66,783			154,708			198,762
Less: Cures		(43,326	)		(31,963	)		(139,826	)		(116,084	)
Less: Paids (including those charged to a deductible or captive)		(11,722	)		(7,305	)		(31,569	)		(20,557	)
Less: Rescissions and denials		(3,168	)		(4,142	)		(10,380	)		(8,699	)
Default inventory at end of period		223,373			235,610			223,373			235,610

Information about the composition of the primary default inventory at September 30, 2010, December 31, 2009 and September 30, 2009 appears in the table below.

	September 30,			December 31,			September 30,
	2010			2009			2009


Total loans delinquent (1)		223,373			250,440			235,610
Percentage of loans delinquent (default rate)		17.67	%		18.41	%		16.92	%

Prime loans delinquent (2)		139,270			150,642			137,789
Percentage of prime loans delinquent (default rate)		13.19	%		13.29	%		11.91	%

A-minus loans delinquent (2)		32,843			37,711			36,335
Percent of A-minus loans delinquent (default rate)		36.73	%		40.66	%		37.95	%

Subprime credit loans delinquent (2)		11,465			13,687			13,432
Percentage of subprime credit loans delinquent (default rate)		45.59	%		50.72	%		48.26	%

Reduced documentation loans delinquent (3)		39,795			48,400			48,054
Percentage of reduced documentation loans delinquent (default rate)		42.49	%		45.26	%		42.85	%

General Notes: (a) For the information presented for the third quarter of 2010, the FICO credit score for a loan with multiple borrowers is the lowest of the borrowers’ “decision FICO scores.” For the information presented prior to the third quarter of 2010, the FICO score for a loan with multiple borrowers was the income weighted average of the “decision FICO scores” for each borrower. A borrower’s “decision FICO score” is determined as follows: if there are three FICO scores available, the middle FICO score is used; if two FICO scores are available, the lower of the two is used; if only one FICO score is available, it is used. This change will make our reporting of FICO credit scores consistent with the FICO credit scores that we use for underwriting purposes.

(b) Servicers continue to pay our premiums for nearly all of the loans in our default inventory, but in some cases, servicers stop paying our premiums. In those cases, even though the loans continue to be included in our default inventory, the applicable loans are removed from our insurance in force and risk in force. Loans where servicers have stopped paying premiums include 13,480 defaults with a risk of $651.4 million as of September 30, 2010.

(1) At September 30, 2010, December 31, 2009 and September 30, 2009 37,420, 45,907 and 46,167 loans in default, respectively, related to Wall Street bulk transactions.

(2) We define prime loans as those having FICO credit scores of 620 or greater, A-minus loans as those having FICO credit scores of 575-619, and subprime credit loans as those having FICO credit scores of less than 575, all as reported to us at the time a commitment to insure is issued. Most A-minus and subprime credit loans were written through the bulk channel. However, we classify all loans without complete documentation as “reduced documentation” loans regardless of FICO score rather than as a prime, “A-minus” or “subprime” loan; in the table above, such loans appear only in the reduced documentation category and they do not appear in any of the other categories.

(3) In accordance with industry practice, loans approved by GSE and other automated underwriting (AU) systems under "doc waiver" programs that do not require verification of borrower income are classified by MGIC as "full documentation." Based in part on information provided by the GSEs, we estimate full documentation loans of this type were approximately 4% of 2007 NIW. Information for other periods is not available. We understand these AU systems grant such doc waivers for loans they judge to have higher credit quality. We also understand that the GSEs terminated their “doc waiver” programs, with respect to new commitments, in the second half of 2008.

Pool insurance notice inventory decreased from 44,231 at December 31, 2009 to 43,168 at September 30, 2010. The pool insurance notice inventory was 40,820 at September 30, 2009.

Entity Information (USD $)	9 Months Ended
Entity Information (USD $)	Sep. 30, 2010	Oct. 25, 2010	Jun. 30, 2009
Entity Registrant Name	MGIC INVESTMENT CORP
Entity Central Index Key	0000876437
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 535,000,000
Entity Common Stock, Shares Outstanding		200,449,588
Document Fiscal Year Focus	2010
Document Fiscal Period Focus	Q3

New Accounting Guidance	9 Months Ended
New Accounting Guidance	Sep. 30, 2010
Notes To Financial Statements [Abstract]
New Accounting Guidance	Note 2 - New Accounting Guidance In January 2010 new accounting guidance was issued that expanded the required disclosures on fair value measurements. The guidance will require the disclosure of transfers in and out of Levels 1 and 2 of the fair value hierarchy and the reasons for those transfers and separate presentation of purchases, sales, issuances and settlements for Level 3 securities, on a gross basis rather than as one net number. The new guidance also clarifies the level of disaggregation required to be disclosed for each class of assets and liabilities and provides clarification on the appropriate disclosures of inputs and valuation techniques used to measure fair value for both recurring and non recurring measurements in Levels 2 and 3. This guidance is effective for interim and annual reporting periods beginning after December 15, 2009, except for the disclosures about purchases, sales, issuances, and settlements for the Level 3 securities. Those disclosures are effective for fiscal years beginning after December 15, 2010, and for interim periods within those fiscal years. We have evaluated the provisions of this guidance and there is no significant impact on our financial statement disclosures.

Document Information	9 Months Ended
Document Information	Sep. 30, 2010
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2010

PARENTHETICAL DATA TO THE CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2010	Dec. 31, 2009
Securities, available-for-sale, at fair value:
Fixed maturities, amortized cost	$ 6,848,738	$ 7,091,840
Shareholders' equity: (note 14)
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	460,000,000	460,000,000
Common stock, shares issued (in shares)	205,046,780	130,163,060
Common stock, shares outstanding (in shares)	200,449,588	125,101,057
Treasury stock, shares at cost (in shares)	4,597,192	5,062,003

Reinsurance	9 Months Ended
Reinsurance	Sep. 30, 2010
Notes To Financial Statements [Abstract]
Reinsurance	Note 4 – Reinsurance The reinsurance recoverable on loss reserves as of September 30, 2010 and December 31, 2009 was $299.2 million and $332.2 million, respectively. Within those amounts, the reinsurance recoverable on loss reserves related to captive agreements was approximately $264 million at September 30, 2010 and $297 million at December 31, 2009. The total fair value of the trust fund assets under our captive agreements at September 30, 2010 was $540 million, compared to $547 million at December 31, 2009. Trust fund assets of $35 million and $41 million were transferred to us as a result of captive terminations during the first nine months of 2010 and 2009, respectively.

Shareholders' equity	9 Months Ended
Shareholders' equity	Sep. 30, 2010
Notes To Financial Statements [Abstract]
Shareholders' equity	Note 14 – Shareholders’ equity In April 2010 we completed the public offering and sale of 74,883,720 shares of our common stock at a price of $10.75 per share. We received net proceeds of approximately $772.4 million, after deducting underwriting discount and offering expenses. The shares of common stock sold were newly issued shares. In the second quarter of 2010 we contributed $200 million of these proceeds to MGIC. On October 1, 2010 we used a portion of these proceeds to pay deferred interest on our convertible junior subordinated debentures as discussed in Note 3. We intend to use the remaining net proceeds from the common stock and convertible notes offerings to provide funds to repay at maturity or repurchase prior to maturity the $78.4 million outstanding principal amount of our 5.625% Senior Notes due in September 2011 and for our general corporate purposes, which may include improving liquidity by providing funds for debt service and increasing the capital of MGIC and other subsidiaries.