Residential mortgage investments classified by collateral type and interest rate characteristics were as follows as of the indicated dates (dollars in thousands):

	Unpaid Principal Balance		Investment Premiums		Amortized Cost Basis		Carrying Amount ^(a)		Net WAC ^(b)			Average Yield^(b⁾
December 31, 2014
Agency Securities:
Fannie Mae/Freddie Mac:
Fixed-rate	$	1,660	$	4	$	1,664	$	1,665		6.63	%		6.45	%
ARMs		10,230,419		328,781		10,559,200		10,800,332		2.51			1.72
Ginnie Mae ARMs		2,983,659		103,911		3,087,570		3,099,168		2.63			1.53
		13,215,738		432,696		13,648,434		13,901,165		2.54			1.69
Residential mortgage loans:
Fixed-rate		1,848		2		1,850		1,850		6.96			5.46
ARMs		3,046		13		3,059		3,059		3.73			3.14
		4,894		15		4,909		4,909		4.95			3.97
Collateral for structured financings		1,997		33		2,030		2,030		8.11			7.62
	$	13,222,629	$	432,744	$	13,655,373	$	13,908,104		2.54			1.69
December 31, 2013
Agency Securities:
Fannie Mae/Freddie Mac:
Fixed-rate	$	2,158	$	6	$	2,164	$	2,167		6.67	%		6.40	%
ARMs		10,675,620		343,452		11,019,072		11,231,057		2.58			1.59
Ginnie Mae ARMs		2,145,639		74,396		2,220,035		2,233,495		2.64			1.57
		12,823,417		417,854		13,241,271		13,466,719		2.59			1.59
Residential mortgage loans:
Fixed-rate		2,633		3		2,636		2,636		6.99			5.62
ARMs		4,244		18		4,262		4,262		3.81			3.46
		6,877		21		6,898		6,898		5.03			4.27
Collateral for structured financings		2,220		37		2,257		2,257		8.09			7.34
	$	12,832,514	$	417,912	$	13,250,426	$	13,475,874		2.59			1.59

(a)	Includes unrealized gains and losses for residential mortgage investments classified as available-for-sale (see NOTE 9).

(b)

Net WAC, or weighted average coupon, is the weighted average interest rate of the mortgage loans underlying the indicated investments net of servicing and other fees as of the indicated balance sheet date. Net WAC is expressed as a percentage calculated on an annualized basis on the unpaid principal balances of the mortgage loans underlying these investments. Average yield is presented for the year then ended, and is based on the cash component of interest income expressed as a percentage calculated on an annualized basis on average amortized cost basis (the “cash yield”) less the effects of amortizing investment premiums. Investment premium amortization is determined using the interest method and incorporates actual and anticipated future mortgage prepayments.