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

	Unpaid Principal Balance		Investment Premiums		Amortized Cost Basis		Carrying Amount ^(a)		Net WAC ^(b)			Average Yield^(b⁾
March 31, 2015
Agency Securities:
Fannie Mae/Freddie Mac:
Fixed-rate	$	1,335	$	4	$	1,339	$	1,340		6.64	%		6.02	%
ARMs		10,381,104		334,577		10,715,681		10,958,273		2.51			1.76
Ginnie Mae ARMs		3,061,079		106,549		3,167,628		3,183,873		2.60			1.45
		13,443,518		441,130		13,884,648		14,143,486		2.53			1.69
Residential mortgage loans:
Fixed-rate		1,701		1		1,702		1,702		6.92			5.67
ARMs		2,891		12		2,903		2,903		3.73			3.22
		4,592		13		4,605		4,605		4.91			4.12
Collateral for structured financings		1,961		32		1,993		1,993		8.11			7.75
	$	13,450,071	$	441,175	$	13,891,246	$	14,150,084		2.53			1.70
December 31, 2014
Agency Securities:
Fannie Mae/Freddie Mac:
Fixed-rate	$	1,660	$	4	$	1,664	$	1,665		6.63	%		6.52	%
ARMs		10,230,419		328,781		10,559,200		10,800,332		2.51			1.68
Ginnie Mae ARMs		2,983,659		103,911		3,087,570		3,099,168		2.63			1.58
		13,215,738		432,696		13,648,434		13,901,165		2.54			1.66
Residential mortgage loans:
Fixed-rate		1,848		2		1,850		1,850		6.96			5.65
ARMs		3,046		13		3,059		3,059		3.73			3.18
		4,894		15		4,909		4,909		4.95			4.09
Collateral for structured financings		1,997		33		2,030		2,030		8.11			7.86
	$	13,222,629	$	432,744	$	13,655,373	$	13,908,104		2.54			1.66

(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 quarter 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.