Mortgage-Backed Securities

The Company classifies its Non-Agency RMBS as senior, senior IO, subordinated, or subordinated IO. The Company also invests in residential, commercial and IO Agency MBS. Senior interests in Non-Agency RMBS are considered to be entitled to the first principal repayments in their pro-rata ownership interests at the acquisition date. The tables below present amortized cost, fair value and unrealized gain/losses of Company's MBS investments as of March 31, 2017 and December 31, 2016.



			March 31, 2017
			(dollars in thousands)
	Principal or Notional Value		Total Premium		Total Discount			Amortized Cost		Fair Value		Gross Unrealized Gains		Gross Unrealized Losses			Net Unrealized Gain/(Loss)
Non-Agency RMBS
Senior	$	3,060,690	$	214	$	(1,361,946	)	$	1,698,958	$	2,438,623	$	739,946	$	(281	)	$	739,665
Senior, interest-only	5,434,402		287,220		—			287,220		239,511		16,095		(63,804		)	$	(47,709	)
Subordinated	662,469		15,360		(212,416		)	465,413		538,459		74,739		(1,693		)	$	73,046
Subordinated, interest-only	263,126		13,627		—			13,627		11,798		103		(1,932		)	$	(1,829	)
Agency MBS
Residential	2,480,534		144,287		—			2,624,821		2,587,928		10,566		(47,459		)	$	(36,893	)
Commercial	1,393,290		37,763		(2,761		)	1,428,292		1,382,734		1,334		(46,892		)	$	(45,558	)
Interest-only	3,248,168		139,313		—			139,313		131,189		877		(9,001		)	$	(8,124	)
Total	$	16,542,679	$	637,784	$	(1,577,123	)	$	6,657,644	$	7,330,242	$	843,660	$	(171,062	)	$	672,598



			December 31, 2016
			(dollars in thousands)
	Principal or Notional Value		Total Premium		Total Discount			Amortized Cost		Fair Value		Gross Unrealized Gains		Gross Unrealized Losses			Net Unrealized Gain/(Loss)
Non-Agency RMBS
Senior	$	3,190,947	$	231	$	(1,412,058	)	$	1,779,120	$	2,511,003	$	732,133	$	(250	)	$	731,883
Senior, interest-only	5,648,339		292,396		—			292,396		253,539		18,674		(57,531		)	(38,857		)
Subordinated	673,259		16,352		(212,734		)	476,877		553,498		77,857		(1,236		)	76,621
Subordinated, interest-only	266,927		13,878		—			13,878		12,024		—		(1,854		)	(1,854		)
Agency MBS
Residential	2,594,570		149,872		—			2,744,442		2,705,978		11,235		(49,699		)	(38,464		)
Commercial	1,331,543		37,782		(2,688		)	1,366,637		1,316,975		175		(49,837		)	(49,662		)
Interest-only	3,356,491		152,175		—			152,175		144,800		1,893		(9,268		)	(7,375		)
Total	$	17,062,076	$	662,686	$	(1,627,480	)	$	6,825,525	$	7,497,817	$	841,967	$	(169,675	)	$	672,292

The table below presents changes in accretable yield, or the excess of the security’s cash flows expected to be collected over the Company’s investment, solely as it pertains to the Company’s Non-Agency RMBS portfolio accounted for according to the provisions of ASC 310-30.



	For the Quarters Ended
	March 31, 2017			March 31, 2016
	(dollars in thousands)
Balance at beginning of period	$	1,550,110		$	1,742,744
Purchases	8,216			20,183
Yield income earned	(68,827		)	(72,169		)
Reclassification (to) from non-accretable difference	23,952			35,783
Sales and deconsolidation	(35		)	—
Balance at end of period	$	1,513,416		$	1,726,541

The table below presents the outstanding principal balance and related amortized cost at March 31, 2017 and December 31, 2016 as it pertains to the Company’s Non-Agency RMBS portfolio accounted for according to the provisions of ASC 310-30.



	For the Quarter Ended		For the Year Ended
	March 31, 2017		December 31, 2016
	(dollars in thousands)
Outstanding principal balance:
Beginning of period	$	3,138,265	$	3,550,698
End of period	$	3,042,276	$	3,138,265
Amortized cost:
Beginning of period	$	1,695,079	$	1,958,726
End of period	$	1,635,565	$	1,695,079

The following tables present the gross unrealized losses and estimated fair value of the Company’s RMBS by length of time that such securities have been in a continuous unrealized loss position at March 31, 2017 and December 31, 2016. All securities in an unrealized loss position have been evaluated by the Company for OTTI as discussed in Note 2(d) of 2016, Form 10-K.



						March 31, 2017
						(dollars in thousands)
	Unrealized Loss Position for Less than 12 Months						Unrealized Loss Position for 12 Months or More						Total
	Estimated Fair Value		Unrealized Losses			Number of Securities	Estimated Fair Value		Unrealized Losses			Number of Securities	Estimated Fair Value		Unrealized Losses			Number of Securities
Non-Agency RMBS
Senior	$	9,776	$	(281	)	2	$	—	$	—		—	$	9,776	$	(281	)	2
Senior, interest-only	82,622		(16,387		)	59	76,566		(47,417		)	91	159,188		(63,804		)	150
Subordinated	27,875		(776		)	4	3,160		(917		)	4	31,035		(1,693		)	8
Subordinated, interest-only	609		(345		)	2	4,963		(1,587		)	2	5,572		(1,932		)	4
Agency MBS
Residential	2,243,923		(45,850		)	109	53,638		(1,609		)	1	2,297,561		(47,459		)	110
Commercial	1,164,212		(43,044		)	580	51,932		(3,848		)	46	1,216,144		(46,892		)	626
Interest-only	65,126		(2,600		)	22	46,816		(6,401		)	15	111,942		(9,001		)	37
Total	$	3,594,143	$	(109,283	)	778	$	237,075	$	(61,779	)	159	$	3,831,218	$	(171,062	)	937



						December 31, 2016
						(dollars in thousands)
	Unrealized Loss Position for Less than 12 Months						Unrealized Loss Position for 12 Months or More						Total
	Estimated Fair Value		Unrealized Losses			Number of Securities	Estimated Fair Value		Unrealized Losses			Number of Securities	Estimated Fair Value		Unrealized Losses			Number of Securities
Non-Agency RMBS
Senior	$	12,384	$	(250	)	3	$	—	$	—		—	$	12,384	$	(250	)	3
Senior, interest-only	96,399		(13,600		)	62	78,516		(43,931		)	86	174,915		(57,531		)	148
Subordinated	56,015		(412		)	7	2,826		(824		)	4	58,841		(1,236		)	11
Subordinated, interest-only	748		(230		)	2	11,276		(1,624		)	3	12,024		(1,854		)	5
Agency MBS
Residential	2,338,910		(48,084		)	106	54,943		(1,615		)	1	2,393,853		(49,699		)	107
Commercial	1,247,923		(45,802		)	646	51,733		(4,035		)	46	1,299,656		(49,837		)	692
Interest-only	63,506		(2,170		)	20	52,963		(7,098		)	16	116,469		(9,268		)	36
Total	$	3,815,885	$	(110,548	)	846	$	252,257	$	(59,127	)	156	$	4,068,142	$	(169,675	)	1002

At March 31, 2017, the Company had the intent to sell ten Agency MBS positions collateralized by commercial property which were in an unrealized loss position. These Commercial Agency MBS positions had an unrealized loss of $2 million at March 31, 2017. Therefore, the Company recorded an other-than-temporary impairment loss for this amount during the current reporting period. There were no other MBS securities at March 31, 2017 that were in an unrealized loss position, and the Company intended to sell, or it was more likely than not that the Company would be required to sell these RMBS before recovery of their amortized cost basis, which may be at their maturity. With respect to RMBS held by consolidated VIEs, the ability of any entity to cause the sale by the VIE prior to the maturity of these RMBS is either expressly prohibited, not probable, or is limited to specified events of default, none of which have occurred as of March 31, 2017.

Gross unrealized losses on the Company’s Agency residential and commercial MBS were $94 million and $100 million as of March 31, 2017 and December 31, 2016, respectively. Given the inherent credit quality of Agency MBS, the Company does not consider any of the current impairments on its Agency MBS to be credit related. In evaluating whether it is more likely than not that it will be required to sell any impaired security before its anticipated recovery, which may be at their maturity, the Company considers the significance of each investment, the amount of impairment, the projected future performance of such impaired securities, as well as the Company’s current and anticipated leverage capacity and liquidity position. Based on these analyses, the Company determined that at March 31, 2017 and December 31, 2016, unrealized losses on its Agency MBS were temporary.

Gross unrealized losses on the Company’s Non-Agency RMBS (excluding Non-Agency IO MBS strips which are reported at fair value with changes in fair value recorded in earnings) were $2 million and $1 million at March 31, 2017 and December 31, 2016, respectively. Based upon the most recent evaluation, the Company does not consider these unrealized losses to be indicative of OTTI and does not believe that these unrealized losses are credit related, but rather are due to other factors. The Company has reviewed its Non-Agency RMBS that are in an unrealized loss position to identify those securities with losses that are other-than-temporary based on an assessment of changes in cash flows expected to be collected for such RMBS, which considers recent bond performance and expected future performance of the underlying collateral.

A summary of the OTTI included in earnings for the quarters ended March 31, 2017 and 2016 is presented below.



	For the Quarter Ended
	March 31, 2017			March 31, 2016
	(dollars in thousands)
Total other-than-temporary impairment losses	$	(2,713	)	$	(4,423	)
Portion of loss recognized in other comprehensive income (loss)	(15,988		)	(6,255		)
Net other-than-temporary credit impairment losses	$	(18,701	)	$	(10,678	)

The following table presents a roll forward of the credit loss component of OTTI on the Company’s Non-Agency RMBS for which a portion of loss was previously recognized in OCI. The table delineates between those securities that are recognizing OTTI for the first time as opposed to those that have previously recognized OTTI.



	For the Quarter Ended
	March 31, 2017			March 31, 2016
	(dollars in thousands)
Cumulative credit loss beginning balance	$	556,485		$	529,112
Additions:
Other-than-temporary impairments not previously recognized	—			10,326
Reductions for securities sold or deconsolidated during the period	(7,443		)	(242		)
Increases related to other-than-temporary impairments on securities with previously recognized other-than-temporary impairments	16,726			352
Reductions for increases in cash flows expected to be collected over the remaining life of the securities	(7,539		)	(172		)
Cumulative credit impairment loss ending balance	$	558,229		$	539,376

Cash flows generated to determine net other-than-temporary credit impairment losses recognized in earnings are estimated using significant unobservable inputs. The significant inputs used to measure the component of OTTI recognized in earnings for the Company’s Non-Agency RMBS are summarized as follows:



	For the Quarter Ended
	March 31, 2017	March 31, 2016
Loss Severity
Weighted Average	64%	58%
Range	63% - 64%	44% - 79%
60+ days delinquent
Weighted Average	19%	20%
Range	11% - 25%	0% - 40%
Credit Enhancement ⁽¹⁾
Weighted Average	22%	28%
Range	0% - 37%	0% - 100%
3 Month CPR
Weighted Average	12%	5%
Range	4% - 24%	0% - 19%
12 Month CPR
Weighted Average	10%	4%
Range	4% - 19%	4% - 21%

(1) Calculated as the combined credit enhancement to the Re-REMIC and underlying from each of their respective capital structures.

The following tables present a summary of unrealized gains and losses at March 31, 2017 and December 31, 2016. IO MBS included in the tables below represent the right to receive a specified portion of the contractual interest cash flows of the underlying principal balance of specific securities. At March 31, 2017, IO MBS had a net unrealized loss of $58 million and had an amortized cost of $440 million. At December 31, 2016, IO MBS had a net unrealized loss of $48 million and had an amortized cost of $458 million. The fair value of IOs at March 31, 2017 and December 31, 2016 was $382 million and $410 million, respectively. All changes in fair value of IOs are reflected in Net Income in the Consolidated Statements of Operations.



			March 31, 2017
			(dollars in thousands)
	Gross Unrealized Gain Included in Accumulated Other Comprehensive Income		Gross Unrealized Gain Included in Cumulative Earnings		Total Gross Unrealized Gain		Gross Unrealized Loss Included in Accumulated Other Comprehensive Income			Gross Unrealized Loss Included in Cumulative Earnings			Total Gross Unrealized Loss
Non-Agency RMBS
Senior	$	739,946	$	—	$	739,946	$	(281	)	$	—		$	(281	)
Senior, interest-only	—		16,095		16,095		—			(63,804		)	(63,804		)
Subordinated	70,572		4,167		74,739		(75		)	(1,618		)	(1,693		)
Subordinated, interest-only	—		103		103		—			(1,932		)	(1,932		)
Agency MBS
Residential	10,566		—		10,566		(47,459		)	—			(47,459		)
Commercial	1,334		—		1,334		(46,892		)	—			(46,892		)
Interest-only	—		877		877		—			(9,001		)	(9,001		)
Total	$	822,418	$	21,242	$	843,660	$	(94,707	)	$	(76,355	)	$	(171,062	)



			December 31, 2016
			(dollars in thousands)
	Gross Unrealized Gain Included in Accumulated Other Comprehensive Income		Gross Unrealized Gain Included in Cumulative Earnings		Total Gross Unrealized Gain		Gross Unrealized Loss Included in Accumulated Other Comprehensive Income			Gross Unrealized Loss Included in Cumulative Earnings			Total Gross Unrealized Loss
Non-Agency RMBS
Senior	$	732,133	$	—	$	732,133	$	(250	)	$	—		$	(250	)
Senior, interest-only	—		18,674		18,674		—			(57,531		)	(57,531		)
Subordinated	74,584		3,273		77,857		(235		)	(1,001		)	(1,236		)
Subordinated, interest-only	—		—		—		—			(1,854		)	(1,854		)
Agency MBS
Residential	11,235		—		11,235		(49,699		)	—			(49,699		)
Commercial	175		—		175		(49,837		)	—			(49,837		)
Interest-only	—		1,893		1,893		—			(9,268		)	(9,268		)
Total	$	818,127	$	23,840	$	841,967	$	(100,021	)	$	(69,654	)	$	(169,675	)

Changes in prepayments, actual cash flows, and cash flows expected to be collected, among other items, are affected by the collateral characteristics of each asset class. The Company chooses assets for the portfolio after carefully evaluating each investment’s risk profile.

The following tables provide a summary of the Company’s MBS portfolio at March 31, 2017 and December 31, 2016.



	March 31, 2017
	Principal or Notional Value at Period-End (dollars in thousands)		Weighted Average Amortized Cost Basis		Weighted Average Fair Value		Weighted Average Coupon		Weighted Average Yield at Period-End ⁽¹⁾
Non-Agency RMBS
Senior	$	3,060,690	$	55.51	$	79.68	4.4	%	15.8	%
Senior, interest-only	5,434,402		5.29		4.41		1.4	%	10.9	%
Subordinated	662,469		70.25		81.28		3.8	%	9.1	%
Subordinated, interest-only	263,126		5.18		4.48		1.0	%	12.8	%
Agency MBS
Residential pass-through	2,480,534		105.82		104.33		3.9	%	3.0	%
Commercial pass-through	1,393,290		102.51		99.24		3.6	%	2.9	%
Interest-only	3,248,168		4.29		4.04		0.8	%	3.6	%

(1) Bond Equivalent Yield at period end.



	December 31, 2016
	Principal or Notional Value at Period-End (dollars in thousands)		Weighted Average Amortized Cost Basis		Weighted Average Fair Value		Weighted Average Coupon		Weighted Average Yield at Period-End ⁽¹⁾
Non-Agency RMBS
Senior	$	3,190,947	$	55.76	$	78.69	4.3	%	15.5	%
Senior, interest-only	5,648,339		5.18		4.49		1.5	%	11.7	%
Subordinated	673,259		70.83		82.21		3.8	%	9.2	%
Subordinated, interest-only	266,927		5.20		4.50		1.1	%	13.5	%
Agency MBS
Residential pass-through	2,594,570		105.78		104.29		3.9	%	3.0	%
Commercial pass-through	1,331,543		102.64		98.91		3.6	%	2.9	%
Interest-only	3,356,491		4.53		4.31		0.8	%	3.5	%

(1) Bond Equivalent Yield at period end.

The following table presents the weighted average credit rating, based on the lowest rating available, of the Company’s Non-Agency RMBS portfolio at March 31, 2017 and December 31, 2016.



	March 31, 2017		December 31, 2016
AAA	0.3	%	0.3	%
AA	0.3	%	0.3	%
A	0.6	%	0.7	%
BBB	0.8	%	0.7	%
BB	2.3	%	3.0	%
B	3.8	%	3.9	%
Below B or not rated	91.9	%	91.1	%
Total	100.0	%	100.0	%

Actual maturities of MBS are generally shorter than the stated contractual maturities. Actual maturities of the Company’s MBS are affected by the contractual lives of the underlying mortgages, periodic payments of principal and prepayments of principal. The following tables provide a summary of the fair value and amortized cost of the Company’s MBS at March 31, 2017 and December 31, 2016 according to their estimated weighted-average life classifications. The weighted-average lives of the MBS in the tables below are based on lifetime expected prepayment rates using an industry prepayment model for the Agency MBS portfolio and the Company’s prepayment assumptions for the Non-Agency RMBS. The prepayment model considers current yield, forward yield, steepness of the interest rate curve, current mortgage rates, mortgage rates of the outstanding loan, loan age, margin, and volatility.



	March 31, 2017
	(dollars in thousands)
	Weighted Average Life
	Less than one year		Greater than one year and less than five years		Greater than five years and less than ten years		Greater than ten years		Total
Fair value
Non-Agency RMBS
Senior	$	13,049	$	559,748	$	1,149,305	$	716,521	$	2,438,623
Senior interest-only	254		40,115		107,971		91,171		239,511
Subordinated	—		91,937		222,181		224,341		538,459
Subordinated interest-only	—		—		11,798		—		11,798
Agency MBS
Residential	—		14,298		2,573,630		—		2,587,928
Commercial	—		46,882		16,676		1,319,176		1,382,734
Interest-only	—		92,969		33,509		4,711		131,189
Total fair value	$	13,303	$	845,949	$	4,115,070	$	2,355,920	$	7,330,242
Amortized cost
Non-Agency RMBS
Senior	$	11,800	$	420,613	$	783,176	$	483,369	$	1,698,958
Senior interest-only	1,532		49,283		135,893		100,512		287,220
Subordinated	—		76,349		183,184		205,880		465,413
Subordinated interest-only	—		—		13,627		—		13,627
Agency MBS
Residential	—		14,296		2,610,525		—		2,624,821
Commercial	—		48,568		17,239		1,362,485		1,428,292
Interest-only	—		95,470		39,191		4,652		139,313
Total amortized cost	$	13,332	$	704,579	$	3,782,835	$	2,156,898	$	6,657,644



	December 31, 2016
	(dollars in thousands)
	Weighted Average Life
	Less than one year		Greater than one year and less than five years		Greater than five years and less than ten years		Greater than ten years		Total
Fair value
Non-Agency RMBS
Senior	$	25,612	$	508,979	$	1,267,000	$	709,412	$	2,511,003
Senior interest-only	417		37,796		115,780		99,546		253,539
Subordinated	—		94,793		238,630		220,075		553,498
Subordinated interest-only	—		—		12,024		—		12,024
Agency MBS
Residential	—		429,869		2,276,109		—		2,705,978
Commercial	—		47,354		16,833		1,252,788		1,316,975
Interest-only	—		75,863		63,715		5,222		144,800
Total fair value	$	26,029	$	1,194,654	$	3,990,091	$	2,287,043	$	7,497,817
Amortized cost
Non-Agency RMBS
Senior	$	21,423	$	403,250	$	868,624	$	485,823	$	1,779,120
Senior interest-only	1,992		50,252		134,642		105,510		292,396
Subordinated	—		76,287		195,538		205,052		476,877
Subordinated interest-only	—		—		13,878		—		13,878
Agency MBS
Residential	—		438,270		2,306,172		—		2,744,442
Commercial	—		49,027		17,247		1,300,363		1,366,637
Interest-only	—		77,598		69,333		5,244		152,175
Total amortized cost	$	23,415	$	1,094,684	$	3,605,434	$	2,101,992	$	6,825,525

The Non-Agency RMBS portfolio is subject to credit risk. The Non-Agency RMBS portfolio is primarily collateralized by Alt-A first lien mortgages. An Alt-A mortgage is a type of U.S. mortgage that, for various reasons, is considered riskier than A-paper, or prime, and less risky than subprime, the riskiest category. Alt-A interest rates, which are determined by credit risk, therefore tend to be between those of prime and subprime home loans. Typically, Alt-A mortgages are characterized by borrowers with less than full documentation, lower credit scores and higher loan-to-value ratios. At origination of the loan, Alt-A mortgage securities are defined as Non-Agency RMBS where (i) the underlying collateral has weighted average FICO scores between 680 and 720 or (ii) the FICO scores are greater than 720 and RMBS have 30% or less of the underlying collateral composed of full documentation loans. At March 31, 2017 and December 31, 2016, 68% of the Non-Agency RMBS collateral was classified as Alt-A, respectively. At March 31, 2017 and December 31, 2016, 13% and 14% of the Non-Agency RMBS collateral was classified as prime, respectively. The remaining Non-Agency RMBS collateral is classified as subprime.

The Non-Agency RMBS in the Portfolio have the following collateral characteristics at March 31, 2017 and December 31, 2016.



	March 31, 2017				December 31, 2016
Weighted average maturity (years)		21.4				21.6
Weighted average amortized loan to value⁽¹⁾		66.2		%		66.5		%
Weighted average FICO⁽²⁾		674				675
Weighted average loan balance (in thousands)		$	320			$	319
Weighted average percentage owner occupied		83.3		%		83.2		%
Weighted average percentage single family residence		65.8		%		65.8		%
Weighted average current credit enhancement		2.3		%		2.3		%
Weighted average geographic concentration of top four states	CA	32.1		%	CA	32.1		%
	FL	8.2		%	FL	8.1		%
	NY	8.1		%	NY	7.9		%
	NJ	2.7		%	NJ	2.7		%

(1) Value represents appraised value of the collateral at the time of loan origination.

(2) FICO as determined at the time of loan origination.

The table below presents the origination year of the underlying loans related to the Company’s portfolio of Non-Agency RMBS at March 31, 2017 and December 31, 2016.



Origination Year	March 31, 2017		December 31, 2016
2003 and prior	3.6	%	3.6	%
2004	4.2	%	4.2	%
2005	20.4	%	20.2	%
2006	37.7	%	38.0	%
2007	31.5	%	31.3	%
2008	1.8	%	1.8	%
2009 and later	0.8	%	0.9	%
Total	100.0	%	100.0	%

Gross realized gains and losses are recorded in “Net realized gains (losses) on sales of investments” on the Company’s Consolidated Statements of Operations. The proceeds and gross realized gains and gross realized losses from sales of investments for the quarters ended March 31, 2017 and 2016 are as follows:



	For the Quarter Ended
	March 31, 2017			March 31, 2016
	(dollars in thousands)
Proceeds from sales	$	20,063		$	270,479
Gross realized gains	5,187			1,695
Gross realized losses	(20		)	(4,369		)
Net realized gain (loss)	$	5,167		$	(2,674	)

Included in the gross realized gains for the quarter ended March 31, 2017 in the table above are exchanges of securities with a fair value of $20 million, the Company exchanged its investment in a re-remic security for the underlying collateral supporting the group related to the exchanged asset. These exchanges were treated as non-cash sales and purchases and resulted in a realized gain of $5 million reflected in earnings for the quarter ended March 31, 2017. There were no such exchanges during the quarter ended March 31, 2016.