7. Fair Value Measurements

ASC Topic 820, Fair Value Measurements and Disclosures establishes a framework for measuring fair value and disclosures about fair value measurements.

Fair value Hierarchy:

ASC Topic 820 specifies a fair value hierarchy based on whether the inputs to valuation techniques used to measure fair value are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect Company-based market assumptions. In accordance with ASC Topic 820, the fair value hierarchy prioritizes model inputs into three broad levels as follows:


• Level 1	–	Quoted prices for identical instruments in active markets. Assets and liabilities classified as Level 1 include US Treasury securities, exchange traded futures contracts, variable rate demand obligations, money market funds and mutual funds.

• Level 2	–	Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. Assets and liabilities classified as Level 2 generally include direct investments in fixed income securities representing municipal, asset-backed and corporate obligations, financial services derivatives (including certain interest rate and currency swap derivatives), certain credit derivative contracts and most long-term debt of variable interest entities consolidated under ASC Topic 810.

• Level 3	–	Model derived valuations in which one or more significant inputs or significant value drivers are unobservable. This hierarchy requires the use of observable market data when available. Assets and liabilities classified as Level 3 include most credit derivative contracts written as part of the financial guarantee business, certain financial services interest rate swap contracts which are not referenced to commonly quoted interest rates, call options on long-term debt, equity interests in Ambac sponsored special purpose entities and certain investments in fixed income securities. Additionally, Level 3 assets and liabilities generally include fixed income securities and loan receivables, as well as certain long-term debt of variable interest entities consolidated under ASC Topic 810.

The following table sets forth the carrying amount and fair value of Ambac's financial assets and liabilities as of March 31, 2012 and December 31, 2011, including the level within the fair value hierarchy at which fair value measurements are categorized. As required by ASC Topic 820, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement.


							Fair Value Measurements Categorized as:
	Carrying Amount			Total Fair Value			Level 1		Level 2			Level 3
March 31, 2012
Financial assets:
Fixed income securities:
Municipal obligations	$	1,971,283		$	1,971,283		$	—	$	1,971,283		$	—
Corporate obligations		1,148,198			1,148,198			—		1,134,831			13,367
Foreign obligations		70,563			70,563			—		70,563			—
U.S. government obligations		129,196			129,196			129,196		—			—
U.S. agency obligations		86,161			86,161			—		84,943			1,218
Residential mortgage-backed securities		1,426,657			1,426,657			—		1,426,657			—
Collateralized debt obligations		43,419			43,419			—		33,580			9,839
Other asset-backed securities		887,656			887,656			—		750,630			137,026
Short term investments		893,822			893,822			869,126		24,696			—
Other investments		100			100			—		—			100
Fixed income securities, pledged as collateral:
U.S. government obligations		284,744			284,744			284,744		—			—
Residential mortgage-backed securities		3,018			3,018			—		3,018			—
Cash		39,931			39,931			39,931		—			—
Restricted cash		2,500			2,500			2,500		—			—
Loans		19,243			17,616			—		—			17,616
Derivative assets:
Interest rate swaps—asset position		385,509			385,509			—		248,131			137,378
Interest rate swaps—liability position		(185,150	)		(185,150	)		—		(26	)		(185,124	)
Future contracts		4,564			4,564			4,564		—			—
Call options on long-term debt		67,735			67,735			—		—			67,735
Other assets		16,023			16,023			—		—			16,023
Variable interest entity assets:
Fixed income securities:
Corporate obligations		2,184,665			2,184,665			—		—			2,184,665
Restricted cash		2,297			2,297			2,297		—			—
Loans		14,661,522			14,649,776			—		189,699			14,460,077

Total financial assets	$	24,143,656		$	24,130,283		$	1,332,358	$	5,938,005		$	16,859,920


Financial liabilities:
Obligations under investment and repurchase agreements	$	547,331		$	547,397		$	—	$	—		$	547,397
Liabilities subject to compromise		1,622,189			195,689			—		195,689			—
Long Term Debt		227,189			833,248			—		—			833,248
Derivative liabilities:
Credit derivatives		201,129			201,129		$	—	$	—		$	201,129
Interest rate swaps—asset position		(949	)		(949	)		—		—			(949	)

Interest rate swaps—liability position		185,593			185,593			—		10,168			175,425
Currency swaps		1,574			1,574			—		1,574			—
Other contracts		129			129			—		129			—
Liabilities for net financial guarantees written		7,505,108			2,858,224			—		—			2,858,224
Variable interest entity liabilities:
Long-term debt		14,666,921			14,642,515			—		11,855,871			2,786,644
Derivative liabilities:
Interest rate swaps—liability position		1,930,259			1,930,259			—		1,930,259			—
Currency swaps—asset position		(15,634	)		(15,634	)		—		(15,634	)		—
Currency swaps—liability position		89,919			89,919			—		89,919			—

Total financial liabilities	$	26,960,758		$	21,469,093		$	—	$	14,067,975		$	7,401,118


							Fair Value Measurements Categorized as:
	Carrying Amount			Total Fair Value			Level 1		Level 2			Level 3
December 31, 2011
Financial assets:
Fixed income securities:
Municipal obligations	$	2,002,999		$	2,002,999		$	—	$	2,002,999		$	—
Corporate obligations		1,127,500			1,127,500			—		1,119,570			7,930
Foreign obligations		94,795			94,795			—		94,795			—
U.S. government obligations		111,562			111,562			111,562		—			—
U.S. agency obligations		86,871			86,871			—		85,647			1,224
Residential mortgage-backed securities		1,412,517			1,412,517			—		1,412,517			—
Collateralized debt obligations		46,237			46,237			—		33,755			12,482
Other asset-backed securities		947,808			947,808			—		871,922			75,886
Short term investments		783,071			783,071			769,204		13,867			—
Other investments		100			100			—		—			100
Fixed income securities, pledged as collateral:
U.S. government obligations		260,802			260,802			260,802		—			—
Residential mortgage-backed securities		2,728			2,728			—		2,728			—
Cash		15,999			15,999			15,999		—			—
Restricted cash		2,500			2,500			2,500		—			—
Loans		18,996			16,934			—		—			16,934
Derivative assets:
Interest rate swaps—asset position		411,652			411,652			—		260,851			150,801
Interest rate swaps—liability position		(242,500	)		(242,500	)		—		(53	)		(242,447	)
Future contracts		—			—			—		—			—
Call options on long-term debt		6,055			6,055			—		—			6,055
Other assets		16,779			16,779			—		—			16,779
Variable interest entity assets:
Fixed income securities:
Corporate obligations		2,199,338			2,199,338			—		—			2,199,338
Restricted cash		2,140			2,140			2,140		—			—
Loans		14,329,515			14,309,134			—		182,140			14,126,994

Total financial assets	$	23,637,464		$	23,615,021		$	1,162,207	$	6,080,738		$	16,372,076


Financial liabilities:
Obligations under investment and repurchase agreements	$	546,546		$	549,043		$	—	$	—		$	549,043
Liabilities subject to compromise		1,622,189			112,233			—		112,233			—
Long Term Debt		223,601			562,043			—		—			562,043
Derivative liabilities:
Credit derivatives		190,653			190,653			—		—			190,653
Interest rate swaps—asset position		(30,859	)		(30,859	)		—		—			(30,859	)
Interest rate swaps—liability position		251,303			251,303			—		9,913			241,390
Futures contracts		627			627			627		—			—
Currency swaps		2,423			2,423			—		2,423			—
Other contracts		361			361			—		361			—
Liabilities for net financial guarantees written		7,547,288			2,642,795			—		—			2,642,795
Variable interest entity liabilities:
Long-term debt		14,288,540			14,255,452			—		12,320,810			1,934,642
Derivative liabilities:
Interest rate swaps—liability position		2,023,974			2,023,974			—		2,023,974			—
Currency swaps—asset position		(27,779	)		(27,779	)		—		(27,779	)		—
Currency swaps—liability position		90,857			90,857			—		90,857			—

Total financial liabilities	$	26,729,724		$	20,623,126		$	627	$	14,532,792		$	6,089,707

Determination of Fair Value:

When available, the Company generally uses quoted market prices to determine fair value, and classifies such items within Level 1. Because many fixed income securities do not trade on a daily basis, pricing sources apply available information through processes such as matrix pricing to calculate fair value. In those cases the items are classified within Level 2. If quoted market prices are not available, fair value is based upon models that use, where possible, current market-based or independently-sourced market parameters. Items valued using valuation models are classified according to the lowest level input or value driver that is significant to the valuation. Thus, an item may be classified in Level 3 even though there may be significant inputs that are readily observable.

The determination of fair value for financial instruments categorized in Level 2 or 3 involves significant judgment due to the complexity of factors contributing to the valuation. Market disruptions make valuation even more difficult and subjective. Third-party sources from which we obtain independent market quotes also use assumptions, judgments and estimates in determining financial instrument values and different third parties may use different methodologies or provide different prices for securities. We believe the potential for differences in third-party pricing levels is particularly significant with respect to residential mortgage-backed and certain other asset-backed securities held in our investment portfolio and referenced in our credit derivative portfolio, due to the low levels of recent trading activity for such securities. In addition, the use of internal valuation models may require assumptions about hypothetical or inactive markets. As a result of these factors, the actual trade value of a financial instrument in the market, or exit value of a financial instrument position by Ambac, may be significantly different from its recorded fair value.

Ambac's financial instruments carried at fair value are mainly comprised of investments in fixed income securities, derivative instruments, call options on certain long-term debt, most variable interest entity assets and liabilities and equity interests in Ambac sponsored special purpose entities. Valuation of financial instruments is performed by Ambac's Finance group using methods approved by senior financial management with consultation from risk management and portfolio managers as appropriate. Preliminary valuation results are discussed with portfolio managers quarterly to assess consistency with market transactions and trends as applicable. Market transactions such as trades or negotiated settlements of similar positions, if any, are reviewed quarterly to validate fair value model results. However many of the financial instruments valued using significant unobservable inputs have very little or no observable market activity. Methods and significant inputs and assumptions used to determine fair values across portfolios are reviewed quarterly by senior financial management. Additionally, changes to fair value methods and assumptions are reviewed with the CEO and audit committee when such changes may be material to the company's financial position or results. Other valuation control procedures specific to particular portfolios are described further below.

We reflect Ambac's own creditworthiness in the fair value of financial liability by including a credit valuation adjustment ("CVA") in the determination of fair value. A decline (increase) in Ambac's creditworthiness as perceived by market participants will generally result in a higher (lower) CVA, thereby lowering (increasing) the fair value of Ambac's financial liabilities as reported.

Fixed Income Securities:

The fair values of fixed income investment securities held by Ambac and its operating subsidiaries are based primarily on market prices received from dealer quotes or alternative pricing sources with reasonable levels of price transparency. Such quotes generally consider a variety of factors, including recent trades of the same and similar securities. For those fixed income investments where quotes were not available, fair values are based on internal valuation models. Key inputs to the internal valuation models include maturity date, coupon and yield curves for asset-type and credit rating characteristics that closely match those characteristics of the specific investment securities being valued. Longer (shorter) expected maturities or higher (lower) yields used in the valuation model will, in isolation, result in decreases (increases) in fair value. Generally, lower credit ratings or longer expected maturities will be accompanied by higher yields used to value a security. At March 31, 2012, approximately 7%, 91%, and 2% of the investment portfolio (excluding variable interest entity investments) was valued using dealer quotes, alternative pricing sources with reasonable levels of price transparency and internal valuation models, respectively.

Ambac performs various review and validation procedures to quoted and modeled prices for fixed income securities, including price variance analyses, missing and static price reviews, overall valuation analyses by senior traders and finance managers and reviews associated with our ongoing impairment analysis. Unusual prices identified through these procedures will be evaluated further against separate broker quotes (if available) or internally modeled prices, and the pricing source values will be challenged as necessary. Price challenges generally result in the use of the pricing source's quote as originally provided or as revised by the source following their internal diligence process. A price challenge may result in a determination that the pricing source cannot provide a reasonable value for a security or cannot adequately support a quote, in which case Ambac would resort to using either other quotes or internal models. Results of price challenges are reviewed and approved by senior traders and finance managers.

Third party quotes represent the only input to the reported fair value of Level 2 fixed income securities. Fixed income securities are classified as Level 3 when the fair value is internally modeled. Information about the valuation inputs for fixed income securities classified as Level 3 is included below:

Corporate obligations: These securities represent interest only strips of investment grade corporate obligations, and at March 31, 2012, one fixed rate investment grade corporate obligation. The fair value of such securities classified as Level 3 was $13,367 and $7,930 at March 31, 2012 and December 31, 2011, respectively. Fair value was calculated using a discounted cash flow approach with the discount rate determined from the yields of corporate bonds from the same issuers. Significant inputs for the fixed rate corporate security valuation at March 31, 2012 were a coupon rate, maturity, and yield of 5.94%, 3.54 years and 2.72%, respectively. Significant inputs for the interest only strips valuation at March 31, 2012 and December 31, 2011 include the following weighted averages:

March 31, 2012

Coupon rate: 0.60%

Maturity: 21.20 years

Yield: 6.81%

December 31, 2011

Coupon rate: 0.60%

Maturity: 21.44 years

Yield: 7.20%

U.S. agency obligations: These notes are secured by separate lease rental agreements with the U.S. Government acting through the General Services Administration. The fair value of such securities classified as Level 3 was $1,218 and $1,224 at March 31, 2012 and December 31, 2011, respectively. Fair value was calculated using a discounted cash flow approach with the yield based on comparable U.S. agency securities. Significant inputs for the valuation at March 31, 2012 and December 31, 2011 include the following weighted averages:

March 31, 2012

Coupon rate: 6.91%

Maturity: 1.24 years

Yield: 2.18%

December 31, 2011

Coupon rate: 6.91%

Maturity: 1.33 years

Yield: 2.13%

Collateralized debt obligations ("CDO"): Securities are floating rate senior notes with the underlying securities of the CDO consist of subordinated bank perpetual preferred securities. The fair value of such securities classified as Level 3 was $9,839 and $12,482 at March 31, 2012 and December 31, 2011, respectively. Fair value was calculated using a discounted cash flow approach with expected future cash flows discounted using a yield curve consistent with the security type and rating. Significant inputs for the valuation at March 31, 2012 and December 31, 2011 include the following weighted averages:

March 31, 2012

Coupon rate: 1.12%

Maturity: 1.50 years

Yield: 11.46%

December 31, 2011

Coupon rate: 0.86%

Maturity: 1.55 years

Yield: 11.79%

Other asset-backed securities: These securities are floating rate investment grade notes collateralized by various asset types. The fair value of such securities classified as Level 3 was $137,026 and $75,886 at March 31, 2012 and December 31, 2011, respectively. Fair value was calculated using a discounted cash flow approach with expected future cash flows discounted using a yield curve consistent with the security type and rating. Significant inputs for the valuation at March 31, 2012 and December 31, 2011 include the following weighted averages:

March 31, 2012

Coupon rate: 1.14%

Maturity: 4.18 years

Yield: 5.99%

December 31, 2011

Coupon rate: 1.41%

Maturity: 3.00 years

Yield: 4.50%

Derivative Instruments:

Ambac's derivative instruments primarily comprise interest rate and credit default swaps, exchange traded futures contracts and call options to repurchase Ambac Assurance surplus notes. Fair value is determined based upon market quotes from independent sources, when available. When independent quotes are not available, fair value is determined using valuation models. These valuation models require market-driven inputs, including contractual terms, credit spreads and ratings on underlying referenced obligations, yield curves and tax-exempt interest ratios. The valuation of certain interest rate and currency swaps as well as all credit derivative contracts also require the use of data inputs and assumptions that are determined by management and are not readily observable in the market. Under ASC Topic 820, Ambac is required to consider its own credit risk when measuring the fair value of derivative and other liabilities. The fair value of net credit derivative liabilities was reduced by $469,692 at March 31, 2012 and $572,523 at December 31, 2011, as a result of incorporating a CVA on Ambac Assurance into the valuation model for these transactions. Interest rate swaps and other derivative liabilities may also require an adjustment to fair value to reflect Ambac Assurance's credit risk. Factors considered in estimating the amount of any Ambac CVA on such contracts include collateral posting provisions, right of set-off with the counterparty, the period of time remaining on the derivatives and the pricing of recent terminations and amendments. Derivative liabilities were reduced by $131,600 at March 31, 2012 and $166,868 at December 31, 2011, as a result of Ambac CVA adjustments to derivative contracts other than credit derivatives.

As described further below, certain valuation models require other inputs that are not readily observable in the market. The selection of a model to value a derivative depends on the contractual terms of, and specific risks inherent in the instrument as well as the availability of pricing information in the market.

For derivatives that are less complex and trade in liquid markets or may be valued primarily by reference to interest rates and yield curves that are observable and regularly quoted, such as interest rate and currency swaps, we utilize vendor-developed models. These models provide the net present value of the derivatives based on contractual terms and observable market data. Downgrades of Ambac Assurance, as guarantor of the financial services derivatives, beginning 2008 have increased collateral requirements and triggered termination provisions in certain interest rate and currency swaps. Increased termination activity since the initial rating downgrades of Ambac Assurance has provided additional information about the current replacement and/or exit value of our financial services derivatives, which may not be fully reflected in our vendor-models but has been incorporated into the fair value of these derivatives at March 31, 2012 and December 31, 2011. These fair value adjustments are applied to individual groups of derivatives based on common attributes such as counterparty type and credit condition, term to maturity, derivative type and net present value. Generally, the need for counterparty (or Ambac) CVAs is mitigated by the existence of collateral posting agreements under which adequate collateral has been posted. Derivative contracts entered into with financial guarantee customers are not typically subject to collateral posting agreements. Counterparty credit risk related to such customer derivative assets is included in our fair value adjustments.

For derivatives that do not trade, or trade in less liquid markets such as credit derivatives, a proprietary model is used because such instruments tend to be unique, contain complex or heavily modified and negotiated terms, and pricing information is not readily available in the market. Derivative fair value models and the related assumptions are continuously re-evaluated by management and enhanced, as appropriate, based on improvements in modeling techniques. Ambac has not made any significant changes to its modeling techniques or related model inputs for the periods presented.

Credit Derivatives ("CDS"):

Fair value of Ambac's CDS is determined using internal valuation models and represents the net present value of the difference between the fees Ambac originally charged for the credit protection and our estimate of what a financial guarantor of comparable credit worthiness would hypothetically charge to provide the same protection at the balance sheet date. Ambac competed in the financial guarantee market, which differs from the credit markets where Ambac-insured obligations may trade. As a financial guarantor, Ambac assumes only credit risk; we do not assume other risks and costs inherent in direct ownership of the underlying reference securities. Additionally, as a result of having the ability to influence our CDS counterparty in certain investor decisions, financial guarantors generally have the ability to actively remediate the credit, potentially reducing the loss given a default. Financial guarantee contracts, including CDS, issued by Ambac and its competitors are typically priced to capture some portion of the spread that would be observed in the capital markets for the underlying (insured) obligation, with minimum pricing constrained by objective estimates of expected loss and financial guarantor required rates of return. Such pricing was well established by historical financial guarantee fees relative to capital market spreads as observed and executed in competitive markets, including in financial guarantee reinsurance and secondary market transactions. Because of this relationship and in the absence of severe credit deterioration, changes in the fair value of our credit default swaps will generally be less than changes in the fair value of the underlying reference obligations.

Key variables used in our valuation of substantially all of our credit derivatives include the balance of unpaid notional, expected term, fair values of the underlying reference obligations, reference obligation credit ratings, assumptions about current financial guarantee CDS fee levels relative to reference obligation spreads and the CVA applied against Ambac Assurance liabilities by market participants. Notional balances, expected remaining term and reference obligation credit ratings are monitored and determined by Ambac's Risk Group. Fair values of the underlying reference obligations are obtained from broker quotes when available, or are derived from other market indications such as new issuance spreads and quoted values for similar transactions. Implicit in the fair values we obtain on the underlying reference obligations are the market's assumptions about default probabilities, default timing, correlation, recovery rates and collateral values.

Broker quotes on the reference obligations named in our CDS contracts represent an input to determine the estimated fair value of the CDS contract. Broker quotes are indicative values for the reference obligation and generally do not represent a bid or doing-business quote for the reference instrument. Such quotes follow methodologies that are generally consistent with those used to value similar assets on the quote providers' own books. Methodologies may differ among brokers but are understood to reflect observable trading activity (when available) and modeling that relies on empirical data and reasonable assumptions. For certain CDS contracts referencing unsecuritized pools of assets, we will obtain counterparty quotes on the credit derivative itself. Such quotes are adjusted to reflect Ambac's own credit risk when determining the fair value of credit derivative liabilities. Third party reference obligation values or specific credit derivative quotes were used in the determination of CDS fair values related to transactions representing 83% of CDS gross par outstanding and 85% of the CDS derivative liability as of March 31, 2012.

When broker quotes for reference obligations are not available, reference obligation prices used in the valuation model are estimated internally based on averages of the quoted prices for other transactions of the same bond type and Ambac rating as well as changes in published credit spreads for securities with similar collateral and ratings characteristics. When price quotes of a similar bond type vary significantly or the number of similar transactions is small, management will consider additional factors, such as specific collateral composition and performance and contractual subordination, to identify similar transactions. Reference obligation prices derived internally as described above were used in the determination of CDS fair values related to transactions representing 17% of CDS gross par outstanding and 15% of the CDS derivative liability as of March 31, 2012.

Ambac's CDS fair value calculations are adjusted for increases in our estimates of expected loss on the reference obligations and observable changes in financial guarantee market pricing. If no adjustment is considered necessary, Ambac maintains the same percentage of the credit spread (over LIBOR) demanded in the market for the reference obligation as existed at the inception of the CDS. Therefore, absent changes in expected loss on the reference obligations or financial guarantee CDS market pricing, the financial guarantee CDS fee used for a particular contract in Ambac's fair value calculations represent a consistent percentage, period to period, of the credit spread determinable from the reference obligation value at the balance sheet date. This results in a CDS fair value balance that fluctuates in proportion with the reference obligation value.

The amount of expected loss on a reference obligation is a function of the probability that the obligation will default and severity of loss in the event of default. Ambac's CDS transactions were all originally underwritten with extremely low expected losses. Both the reference obligation spreads and Ambac's CDS fees at the inception of these transactions reflect these low expected losses. When reference obligations experience credit deterioration, there is an increase in the probability of default on the obligation and, therefore, an increase in expected loss. Ambac reflects the effects of changes in expected loss on the fair value of its CDS contracts by increasing the percentage of the reference obligation spread (over LIBOR) which would be captured as a CDS fee ("relative change ratio") at the valuation date, resulting in a higher mark-to-market loss on our CDS relative to any price decline on the reference obligation. The fundamental assumption is that financial guarantee CDS fees will increase relative to reference obligation spreads as the underlying credit quality of the reference obligation deteriorates and approaches payment default. For example, if the credit spread of an underlying reference obligation was 80 basis points at the inception of a transaction and Ambac received a 20 basis point fee for issuing a CDS on that obligation, the relative change ratio, which represents the CDS fee to cash market spread Ambac would utilize in its valuation calculation, would be 25%. If the reference obligation spread increased to 100 basis points in the current reporting period, absent any observable changes in financial guarantee CDS market pricing or credit deterioration, Ambac's current period CDS fee would be computed by multiplying the current reference obligation spread of 100 basis points by the relative change ratio of 25%, resulting in a 25 basis point fee. Thus, the model indicates we would need to receive an additional 5 basis points (25 basis points currently less the 20 basis points contractually received) for issuing a CDS in the current reporting period for this reference obligation. We would then discount the product of the notional amount of the CDS and the 5 basis point hypothetical CDS fee increase, over the weighted average life of the reference obligation to compute the current period mark-to-market loss. Using the same example, if the reference obligation spread increased to 100 basis points and there was credit deterioration as evidenced by an internal rating downgrade which increased the relative change ratio from 25% to 35%, we would estimate a 15 basis point hypothetical CDS fee increase in our model (35% of 100 basis points reference obligation spread, or 35 basis points currently, less the 20 basis points contractually received). Therefore, we would record a higher mark-to-market loss based on the computations described above absent any observable changes in financial guarantee CDS market pricing.

We do not adjust the relative change ratio until an actual internal rating downgrade has occurred unless we observe new pricing on financial guarantee CDS contracts. However, because we have active surveillance procedures in place for our entire CDS portfolio, particularly for transactions at or near a below investment grade threshold, we believe it is unlikely that an internal downgrade would lag the actual credit deterioration of a transaction for any meaningful time period. The factors used to increase the relative change ratio are based on rating agency probability of default percentages determined by management to be appropriate for the relevant bond type. That is, the probability of default associated with the respective tenor and internal rating of each CDS transaction is utilized in the computation of the relative change ratio in our CDS valuation model. The new relative change ratio in the event of an internal downgrade of the reference obligation is calculated as the weighted average of: (i) a given transaction's inception relative change ratio and (ii) a ratio of 100%. The weight given to the inception relative change ratio is 100% minus the current probability of default (i.e. the probability of non-default) and the weight given to using a 100% relative change ratio is the probability of default. For example, assume a transaction having an inception relative change ratio of 33% is downgraded to B- during the period, at which time it has an estimated remaining life of 8 years. If the estimated probability of default for an 8 year, B- rated credit of this type is 60% then the revised relative change ratio will be 73.2%. The revised relative change ratio can be calculated as 33% x (100%-60%) + 100% x 60% = 73.2%.

As noted above, reference obligation spreads incorporate market perceptions of default probability and loss severity, as well as liquidity risk and other factors. Loss severities are generally correlated to default probabilities during periods of economic stress. By increasing the relative change ratio in our calculations proportionally to default probabilities, Ambac incorporates into its CDS fair value the higher expected loss on the reference obligation (probability of default x loss severity), by increasing the portion of reference obligation spread that should be paid to the CDS provider.

Ambac incorporates its own credit risk into the valuation of its CDS liabilities by applying a CVA to the calculations described above. Under our methodology, determination of the CDS fair value requires estimating hypothetical financial guarantee CDS fees for a given credit at the valuation date and estimating the present value of those fees. Our approach begins with pricing in the risk of default of the reference obligation using that obligation's credit spread. The widening of the reference obligation spread results in a mark-to-market loss to Ambac, as the credit protection seller, and a gain to the credit protection buyer because the cost of credit protection on the reference obligation (ignoring CDS counterparty credit risk) will be greater than the amount of the actual contractual CDS fees. The Ambac CVA is a percentage applied to the estimated CDS liability fair value otherwise calculated as described above. The Ambac CVA is estimated using relevant data points, including quoted prices of securities guaranteed by Ambac Assurance which indicate the value placed by market participants on Ambac Assurance's insurance obligations and the fair value of Ambac Assurance surplus notes. The resulting Ambac CVA percentage used in the valuation of CDS liabilities was 70% and 75% as of March 31, 2012 and December 31, 2011, respectively. In instances where narrower reference obligation spreads result in a CDS asset to Ambac, those hypothetical future CDS fees are discounted at a rate which incorporates our counterparty's credit spread (i.e. the discount rate used is LIBOR plus the current credit spread of the counterparty).

In addition, when there are sufficient numbers of new observable transactions, negotiated settlements or other market indications of a general change in market pricing trends for CDS on a given bond type, management will adjust its assumptions about the percentage of reference obligation spreads captured as CDS fees to match the current market. No such adjustments were made during the periods presented. Ambac is not transacting CDS business currently and other guarantors have stated they have exited this product. Additionally, there have been no negotiated settlements of CDS contracts during the periods presented.

Key variables which impact the "Realized gains and losses and other settlements" component of "Net change in fair value of credit derivatives" in the Consolidated Statements of Total Comprehensive Income are the most readily observable variables since they are based solely on the CDS contractual terms and cash settlements. Those variables include premiums received and accrued and losses paid and payable on written credit derivative contracts for the appropriate accounting period. Losses paid and payable reported in "Realized gains and losses and other settlements" include those arising after a credit event that requires a payment under the contract terms has occurred or in connection with a negotiated termination of a contract. The remaining key variables described above impact the "Unrealized gains (losses)" component of "Net change in fair value of credit derivatives." The net notional outstanding of Ambac's CDS contracts were $13,643,364 and $14,166,612 at March 31, 2012 and December 31, 2011, respectively.

Credit derivative liabilities at March 31, 2012 and December 31, 2011 had a combined fair value of $201,129 and $190,653, respectively, and related to underlying reference obligations that are classified as either CLOs or Other. Information about the above described model inputs used to determine the fair value of each class of credit derivatives as of March 31, 2012 and December 31, 2011is summarized below:


As of March 31, 2012
	CLOs			Other⁽¹⁾
Notional outstanding	$	8,049,334		$	3,826,188
Weighted average reference obligation price		94.0			84.5
Weighted average life (WAL) in years		2.5			4.7
Weighted average credit rating		AA-			A
Weighted average relative change ratio		34.4	%		38.3	%
CVA percentage		70	%		70	%
Fair value of derivative liabilities	$	(51,688	)	$	(93,043	)


As of December 31, 2011
	CLOs			Other⁽¹⁾
Notional outstanding	$	8,228,577		$	4,099,766
Weighted average reference obligation price		92.5			84.3
Weighted average life (WAL) in years		2.7			4.7
Weighted average credit rating		AA-			A
Weighted average relative change ratio		34.4	%		38.5	%
CVA percentage		75	%		75	%
Fair value of derivative liabilities	$	(54,320	)	$	(86,526	)

(1)

Excludes contracts for which fair values are based on credit derivative quotes rather than reference obligation quotes. Such contracts have a combined notional outstanding of $1,767,842, WAL of 9.0 years and liability fair value of ($56,398) as of March 31, 2012. Other inputs to the valuation of these transactions at March 31, 2012 include weighted average quotes of 13% of notional, weighted average rating of A and Ambac CVA percentage of 70%. As of December 31, 2011, these contracts had a combined notional outstanding of $1,838,269, WAL of 9.0 years and liability fair value of ($49,807). Other inputs to the valuation of these transactions at December 31, 2011 include weighted average quotes of 11% of notional, weighted average rating of A+ and Ambac CVA percentage of 75%.

Significant unobservable inputs for credit derivatives include WAL, credit rating, relative change ratio and CVA percentage. A longer (shorter) WAL, lower (higher) reference obligation credit rating, higher (lower) relative change ratio or lower (higher) CVA percentage, in isolation, would result in an increase (decrease) in the fair value liability measurement. A change in credit rating of a reference obligation in our model will generally result in a directionally opposite change in the relative change ratio. Also, a shorter (longer) WAL will generally correspond with a lower (higher) CVA percentage.

Call options on long-term debt:

The fair value of Ambac Assurance's options to repurchase Ambac Assurance surplus notes at a discount to par is estimated based on a combination of internal discounted cash flow analysis and market observations. The discounted cash flow analysis uses multiple discount rate scenarios to determine the present value of the surplus notes assuming exercise and non-exercise of the options, with the difference representing the option value under that scenario. The results are probability weighted to determine the recorded option value. The weighted average discount rates used were 24.91% at March 31, 2012 and 36.57% at December 31, 2011. The board of directors of Ambac Assurance has approved the exercise of all options to purchase surplus notes issued by Ambac Assurance. The exercise of such options also requires the approval of OCI and the Rehabilitator of the Segregated Account. Ambac Assurance is seeking such approvals. There can be no assurance that such approvals will be obtained.

Financial Guarantees:

Fair value of net financial guarantees written represents our estimate of the cost to Ambac to completely transfer its insurance obligation to another financial guarantor of comparable credit worthiness. In theory, this amount should be the same amount that another financial guarantor of comparable credit worthiness would hypothetically charge in the market place, on a present value basis, to provide the same protection as of the balance sheet date.

This fair value estimate of financial guarantees is presented on a net basis and includes direct and assumed contracts written, which represent our liability, net of ceded reinsurance contracts, which represent our asset. The fair value estimate of direct and assumed contracts written is based on the sum of the present values of (i) unearned premium reserves; and (ii) loss and loss expense reserves, including claims presented and not paid as a result of the claim moratorium imposed by the Rehabilitation Court on March 24, 2010. The fair value estimate of ceded reinsurance contracts is based on the sum of the present values of (i) deferred ceded premiums net of ceding commissions; and (ii) reinsurance recoverables on paid and unpaid losses.

Key variables are par amounts outstanding (including future periods for the calculation of future installment premiums), expected term, discount rate, and expected net loss and loss expense payments. Net par outstanding is monitored by Ambac's Risk Group. With respect to the discount rate, ASC Topic 820 requires that the nonperformance risk of a financial liability be included in the estimation of fair value. This nonperformance risk would include considering Ambac Assurance's own credit risk in the fair value of financial guarantees we have issued, thus the estimated fair value for direct contracts written included an Ambac CVA to reflect Ambac's credit risk. The Ambac CVA was 70% and 75% as of March 31, 2012 and December 31, 2011, respectively. Refer to "Credit Derivatives" above for additional information on the determination of the CVA. Refer to Note 6 for additional information on factors which influence our estimate of loss and loss expenses. The estimated fair value of ceded reinsurance contracts factors in any adjustments related to the counterparty credit risk we have with reinsurers.

There are a number of factors that limit our ability to accurately estimate the fair value of our financial guarantees. The first limitation is the lack of observable pricing data points as a result of Ambac no longer writing new financial guarantee business. Additionally, although the fair value accounting guidance for liabilities requires a company to consider the cost to completely transfer its obligation to another party of comparable credit worthiness, our primary insurance obligation is irrevocable and thus there is no established active market for transferring such obligations. Variables which are not incorporated in our current fair value estimate of financial guarantees include the credit spreads of the underlying insured obligations, the underlying ratings of those insured obligations and assumptions about current financial guarantee premium levels relative to the underlying insured obligations' credit spreads.

Liabilities Subject to Compromise:

The fair value of Ambac's debt included in Liabilities Subject to Compromise is based on quoted market prices.

Long-term Debt:

The fair value of surplus notes issued by Ambac Assurance and classified as long-term debt is internally estimated considering market transactions when available and internally developed discounted cash flow models. Surplus notes were initially recorded at fair value at the date of issuance. In subsequent periods, surplus notes are carried at their face value less unamortized discount.

Other Financial Assets and Liabilities:

The fair values of Ambac's equity interest in Ambac sponsored special purpose entities (included in Other assets), Loans, and Obligations under investment and repurchase agreements are estimated based upon internal valuation models that discount expected cash flows using discount rates consistent with the credit quality of the obligor after considering collateralization.

Variable Interest Entity Assets and Liabilities:

The financial assets and liabilities of VIEs consolidated under ASC Topic 810 consist primarily of fixed income securities, loans receivable, derivative instruments and debt instruments and are generally carried at fair value. These consolidated VIEs are securitization entities which have liabilities and/or assets guaranteed by Ambac Assurance. The fair values of VIE debt instruments are determined using the same methodologies used to value Ambac's fixed income securities in its investment portfolio as described above. VIE debt fair value is based on market prices received from dealer quotes or alternative pricing sources with reasonable levels of price transparency. Such quotes are considered Level 2 and generally consider a variety of factors, including recent trades of the same and similar securities. For those VIE debt instruments where quotes were not available, the debt instrument fair values are considered Level 3 and are based on internal discounted cash flow models. Comparable to the sensitivities of investments in fixed income securities described above, longer (shorter) expected maturities or higher (lower) yields used in the valuation model will, in isolation, result in decreases (increases) in fair value liability measurement for VIE debt. VIE debt instruments considered Level 3 include fixed rate, floating rate and zero coupon notes secured by various asset types, primarily European ABS. Information about the valuation inputs for the various VIE debt categories classified as Level 3 is as follows:

European ABS transactions: The fair value of such obligations classified as Level 3 was $2,786,644 and $1,934,642 at March 31, 2012 and December 31, 2011, respectively. Fair values were calculated by using a discounted cash flow approach. The discount rates used were based on the rates implied from the third party quoted values (Level 2) for comparable notes from the same securitization. Significant inputs for the valuation at March 31, 2012 and December 31, 2011 include the following weighted averages:

March 31, 2012

Coupon rate: 1.64%

Maturity: 13.24 years

Yield: 4.10%

December 31, 2011

Coupon rate: 1.56%

Maturity: 11.99 years

Yield: 3.90%

VIE derivative asset and liability fair values are determined using valuation models. When specific derivative contractual terms are available and may be valued primarily by reference to interest rates, foreign exchange rates and yield curves that are observable and regularly quoted the derivatives are valued using vendor-developed models. Other derivatives within the VIEs that include significant unobservable valuation inputs are valued using internally developed models. VIE derivative fair value balances at March 31, 2012 and December 31, 2011 were developed using vendor-developed models and do not use significant unobservable inputs.

The fair value of VIE assets are obtained from market quotes when available. Typically the asset fair values are not readily available from market quotes and are estimated internally. The consolidated VIEs are securitization entities in which net cash flows from assets and derivatives (after adjusting for financial guarantor cash flows and other expenses) will be paid out to note holders or equity interests. Our valuation of VIE assets (fixed income securities or loans), therefore, are derived from the fair value of notes and derivatives, as described above, adjusted for the fair value of cash flows from Ambac's financial guarantee. The fair value of financial guarantee cash flows include: (i) estimated future premiums discounted at a rate consistent with that implicit in the fair value of the VIE's liabilities and (ii) internal estimates of future loss payments by Ambac discounted at a rate that includes Ambac's own credit risk. Excluding changes in estimated financial guarantee cash flows, changes in the fair value of VIE assets will be accompanied by corresponding and offsetting changes in the fair value of VIE liabilities plus VIE derivatives. Higher (lower) estimated future premiums or lower (higher) estimated loss payments on financial guarantee policies in isolation will result in increases (decreases) in the fair value measurement of VIE assets. Changes in financial guarantee estimated premiums and loss payments are generally independent. A higher CVA will reduce the fair value of expected claim payments and therefore increase VIE asset measures. The amount of CVA is generally independent of other significant inputs to the calculation of VIE assets. Estimated future premium payments to be paid by the VIEs were discounted at a weighted average rate of 7.2% and 8.4% at March 31, 2012 and December 31, 2011, respectively. The value of future loss payments to be paid by Ambac to the VIEs was adjusted to include an Ambac CVA appropriate for the term of expected Ambac claim payments.

The following tables present the changes in the Level 3 fair value category for the three months ended March 31, 2012 and 2011. Ambac classifies financial instruments in Level 3 of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level 3 financial instruments typically also rely on a number of inputs that are readily observable either directly or indirectly. Thus, the gains and losses presented below include changes in the fair value related to both observable and unobservable inputs.

Level-3 financial assets and liabilities accounted for at fair value


										VIE Assets and Liabilities
Three months ended March 31, 2012	Investments			Other assets			Derivatives			Investments			Loans			Derivatives		Long-term debt			Total
Balance, beginning of period	$	97,522		$	16,779		$	(486,775	)	$	2,199,338		$	14,126,994			—	$	(1,934,642	)	$	14,019,216
Additions of VIEs consolidated		—			—			—			—			—			—		—			—
Total gains/(losses) realized and unrealized:																	—
Included in earnings		(49	)		(756	)		122,327			(82,816	)		166,665			—		(136,563	)		68,808
Included in other comprehensive income		7,814			—			—			68,143			415,857			—		(63,205	)		428,609
Purchases		—			—			—			—			—			—		—			—
Issuances		—			—			—			—			—			—		—			—
Sales		—			—			—			—			—			—		—			—
Settlements		(2,742	)		—			8,832			—			(249,439	)		—		13,030			(230,319	)
Transfers in Level 3		58,905			—			—			—			—			—		(665,264	)		(606,359	)
Transfers out of Level 3		—			—			—			—			—			—		—			—
Deconsolidation of VIEs		—			—			—			—			—			—		—			—

Balance, end of period	$	161,450		$	16,023		$	(355,616	)	$	2,184,665		$	14,460,077		$	—	$	(2,786,644	)	$	13,679,955

The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	$	—		$	(756	)	$	107,245		$	(82,816	)	$	167,146		$	—	$	(136,563	)	$	54,256


									VIE Assets and Liabilities
Three months ended March 31, 2011	Investments			Other Assets		Derivatives			Investments			Loans			Derivatives			Long-term debt			Total
Balance, beginning of period	$	199,172		$	17,909	$	(195,933	)	$	1,904,361		$	15,800,918		$	4,511		$	(1,856,366	)	$	15,874,572
Total gains/(losses) realized and unrealized:
Included in earnings		(50	)		1,096		17,645			(28,844	)		(49,464	)		(4,511	)		29,749			(34,739	)
Included in other comprehensive income		3,223			—		—			54,174			435,170			—			(52,185	)		440,382
Purchases		—			—		—			—			—			—			—			—
Issuances		—			—		—			—			—			—			—			—
Sales		—			—		—			—			—			—			—			—
Settlements		(2,269	)		—		(11,325	)		—			(262,311	)		—			(873	)		(276,778	)
Transfers in Level 3		—			—		—			—			—			—			(50,125	)		(50,125	)
Transfers out of Level 3		—			—		—			—			—			—			57,106			57,106
Deconsolidation of VIEs		—			—		—			—			(1,894,967	)		—			—			(1,894,967	)

Balance, end of period	$	200,076		$	19,005	$	(189,613	)	$	1,929,691		$	14,029,346		$	—		$	(1,872,694	)	$	14,115,811

The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	$	—		$	1,096	$	13,342		$	(28,844	)	$	(49,464	)	$	(4,511	)	$	29,749		$	(38,632	)

The tables below provide roll-forward information by class of investments and derivatives measured using significant unobservable inputs. This information is provided for the three months ended March 31, 2012 and 2011, as required by ASC Topic 820.


Three months ended March 31, 2012	Collateralized Debt Obligations			Other Asset Backed Securities		Corporate Obligations			U.S. Agency Obligations			Total Investments
Balance, beginning of period	$	12,482		$	75,886	$	7,930		$	1,224		$	97,522
Total gains/(losses) realized and unrealized:
Included in earnings		(2	)		—		(46	)		(1	)		(49	)
Included in other comprehensive income		101			8,072		(354	)		(5	)		7,814
Purchases		—			—		—			—			—
Issuances		—			—		—			—			—
Sales		—			—		—			—			—
Settlements		(2,742	)		—		—			—			(2,742	)
Transfers in Level 3		—			53,068		5,837			—			58,905
Transfers out of Level 3		—			—		—			—			—

Balance, end of period	$	9,839		$	137,026	$	13,367		$	1,218		$	161,450

The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	$	—		$	—	$	—		$	—		$	—

Level 3 – Investments by class


Three months ended March 31, 2011	Collateralized Debt Obligations			Other Asset Backed Securities			Corporate Obligations			U.S. Agency Obligations			Total Investments
Balance, beginning of period	$	30,433		$	159,473		$	8,069		$	1,197		$	199,172
Additions of VIEs for ASC 2009-17
Total gains/(losses) realized and unrealized:
Included in earnings		(6	)		—			(43	)		(1	)		(50	)
Included in other comprehensive income		1,133			2,190			(90	)		(10	)		3,223
Purchases		—			—			—			—			—
Issuances		—			—			—			—			—
Sales		—			—			—			—			—
Settlements		(1,533	)		(736	)		—			—			(2,269	)
Transfers in Level 3		—			—			—			—			—
Transfers out of Level 3		—			—			—			—			—

Balance, end of period	$	30,027		$	160,927		$	7,936		$	1,186		$	200,076

The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	$	—		$	—		$	—		$	—		$	—

Level 3 – Derivatives by class


Three months ended March 31, 2012	Interest Rate Swaps			Credit Derivatives			Currency Swaps		Call Options on Long-term debt		Total Derivatives
Balance, beginning of period	$	(302,177	)	$	(190,653	)	$	—	$	6,055	$	(486,775	)
Additions of VIEs for ASC 2009-17
Total gains/(losses) realized and unrealized:
Included in earnings		67,869			(7,222	)		—		61,680		122,327
Included in other comprehensive income		—			—			—		—		—
Purchases		—			—			—		—		—
Issuances		—			—			—		—		—
Sales		—			—			—		—		—
Settlements		12,086			(3,254	)		—		—		8,832
Transfers in Level 3		—			—			—		—		—
Transfers out of Level 3		—			—			—		—		—
Deconsolidation of VIEs		—			—			—		—		—

Balance, end of period	$	(222,222	)	$	(201,129	)	$	—	$	67,735	$	(355,616	)

The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	$	61,598		$	(16,033	)	$	—	$	61,680	$	107,245

Level 3 – Derivatives by class


Three months ended March 31, 2011	Interest Rate Swaps			Credit Derivatives			Currency Swaps		Call Options on Long-term debt		Total Derivatives
Balance, beginning of period	$	25,750		$	(221,683	)	$	—	$	—	$	(195,933	)
Additions of VIEs for ASC 2009-17
Total gains/(losses) realized and unrealized:
Included in earnings		9,823			(8,903	)		—		16,725		17,645
Included in other comprehensive income		—			—			—		—		—
Purchases		—			—			—		—		—
Issuances		—			—			—		—		—
Sales		—			—			—		—		—
Settlements		(6,002	)		(5,323	)		—		—		(11,325	)
Transfers in Level 3		—			—			—		—		—
Transfers out of Level 3		—			—			—		—		—
Deconsolidation of VIEs		—			—			—		—		—

Balance, end of period	$	29,571		$	(235,909	)	$	—	$	16,725	$	(189,613	)

The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date	$	13,800		$	(17,183	)	$	—	$	16,725	$	13,342

Invested assets and VIE long-term debt are transferred into Level 3 when internal valuation models that include significant unobservable inputs are used to estimate fair value. All such securities that have internally modeled fair values have been classified as Level 3 as of March 31, 2012 and 2011. Derivative instruments are transferred into Level 3 when the use of unobservable inputs becomes significant to the overall valuation. All transfers into and out of Level 3 represent transfers between Level 3 and Level 2. There were no transfers between Level 1 and Level 2 for the periods presented. All transfers between fair value hierarchy Levels 1, 2, and 3 are recognized at the beginning of each accounting period.

Gains and losses (realized and unrealized) relating to Level 3 assets and liabilities included in earnings for the three months ended March 31, 2012 and 2011 are reported as follows:


	Net investment income			Realized gains or (losses) and other settlements on credit derivative contracts		Unrealized gains or (losses) on credit derivative contracts			Derivative products revenues (interest rate swaps)		Income (loss) on variable interest entities			Other income
Three months ended 2012
Total gains or losses included in earnings for the period	$	(49	)	$	3,254	$	(10,476	)	$	67,869	$	(52,714	)	$	60,924
Changes in unrealized gains or losses relating to the assets and liabilities still held at the reporting date		—			—		(16,033	)		61,598		(52,233	)		60,924
Three months ended 2011
Total gains or losses included in earnings for the period	$	(50	)	$	5,323	$	(14,226	)	$	26,548	$	(53,070	)	$	17,821
Changes in unrealized gains or losses relating to the assets and liabilities still held at the reporting date		—			—		(17,183	)		13,800		(53,070	)		17,821