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⁾
September 30, 2015
Agency Securities:
Fannie Mae/Freddie Mac:
Fixed-rate	$	938	$	2	$	940	$	941		6.62	%		6.04	%
ARMs		10,026,213		319,307		10,345,520		10,563,013		2.53			1.48
Ginnie Mae ARMs		3,265,244		112,189		3,377,433		3,388,900		2.60			1.24
		13,292,395		431,498		13,723,893		13,952,854		2.54			1.42
Residential mortgage loans:
Fixed-rate		1,193		1		1,194		1,194		6.77			4.95
ARMs		2,729		11		2,740		2,740		3.73			3.21
		3,922		12		3,934		3,934		4.65			3.74
Collateral for structured financings		1,888		31		1,919		1,919		8.11			7.87
	$	13,298,205	$	431,541	$	13,729,746	$	13,958,707		2.55			1.43
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.