
(in thousands)	At March 31, 2022		At December 31, 2021

Single family	$	48,994	$	128,041
CRE, multifamily and SBA	10,156		48,090
Total	$	59,150	$	176,131


	Quarter Ended March 31,
(in thousands)	2022		2021

Single family	$	323,070	$	573,040
CRE, multifamily and SBA	49,137		257,717
Total	$	372,207	$	830,757

Gain on loan origination and sale activities, including the effects of derivative risk management instruments, consisted of the following:


	Quarter Ended March 31,
(in thousands)	2022		2021

Single family	$	6,169	$	26,187
CRE, multifamily and SBA	2,105		7,272
Total	$	8,274	$	33,459

The Company's portfolio of loans serviced for others is primarily comprised of loans held in U.S. government and agency MBS issued by Fannie Mae, Freddie Mac and Ginnie Mae. The unpaid principal balance of loans serviced for others is as follows:


(in thousands)	At March 31, 2022		At December 31, 2021

Single family	$	5,545,145	$	5,539,180
CRE, multifamily and SBA	2,035,801		2,031,087
Total	$	7,580,946	$	7,570,267

The Company has made representations and warranties that the loans sold meet certain requirements. The Company may be

required to repurchase mortgage loans or indemnify loan purchasers due to defects in the origination process of the loan, such

as documentation errors, underwriting errors and judgments, appraisal errors, early payment defaults and fraud.

The following is a summary of changes in the Company's liability for estimated single-family mortgage repurchase losses:


	Quarter Ended March 31,
(in thousands)	2022		2021

Balance, beginning of period	$	1,312	$	2,122
Additions, net of adjustments (1)	358		(20)
Realized (losses) recoveries, net (2)	(32)		(161)
Balance, end of period	$	1,638	$	1,941

(1) Includes additions for new loan sales and changes in estimated probable future repurchase losses on previously sold loans.

(2) Includes principal losses and accrued interest on repurchased loans, "make-whole" settlements, settlements with claimants and certain related expenses.

The Company has agreements with certain investors to advance scheduled principal and interest amounts on delinquent loans. Advances are also made to fund the foreclosure and collection costs of delinquent loans prior to the recovery of reimbursable amounts from investors or borrowers. Advances of $2.7 million and $1.9 million were recorded in other assets as of March 31, 2022 and December 31, 2021, respectively.

When the Company has the unilateral right to repurchase Ginnie Mae pool loans it has previously sold (generally loans that are more than 90 days past due), the Company records the balance of the loans as other assets and other liabilities. At March 31, 2022 and December 31, 2021, delinquent or defaulted mortgage loans currently in Ginnie Mae pools that the Company has recognized on its consolidated balance sheets totaled $10 million and $12 million, respectively.

Revenue from mortgage servicing, including the effects of derivative risk management instruments, consisted of the following:


	Quarter Ended March 31,
(in thousands)	2022		2021

Servicing income, net:
Servicing fees and other	$	8,321	$	8,913
Amortization of single family MSRs (1)	(3,425)		(5,693)
Amortization of multifamily and SBA MSRs	(1,712)		(1,344)
Total	3,184		1,876
Risk management, single family MSRs:
Changes in fair value of MSRs due to assumptions (2)	10,303		11,463
Net gain (loss) from economic hedging	(10,183)		(12,591)
Total	120		(1,128)

Loan servicing income (loss)	$	3,304	$	748

(1) Represents changes due to collection/realization of expected cash flows and curtailments.

(2) Principally reflects changes in model assumptions, including prepayment speed assumptions, which are primarily affected by changes in mortgage interest rates.


	Quarter Ended March 31,
(in thousands)	2022		2021

Beginning balance	$	61,584	$	49,966
Additions and amortization:
Originations	3,916		6,616

Amortization (1)	(3,425)		(5,693)
Net additions and amortization	491		923
Changes in fair value assumptions (2)	10,303		11,463
Ending balance	$	72,378	$	62,352

(1) Represents changes due to collection/realization of expected cash flows and curtailments.

(2) Principally reflects changes in model assumptions, including prepayment speed assumptions, which are primarily affected by changes in mortgage interest rates.

Key economic assumptions used in measuring the initial fair value of capitalized single family MSRs were as follows:


	Quarter Ended March 31,
(rates per annum) (1)	2022		2021

Constant prepayment rate ("CPR") (2)	9.38	%	8.37	%
Discount rate	8.34	%	8.37	%

For single family MSRs, we use a discounted cash flow valuation technique which utilizes CPRs and discount rates as significant unobservable inputs as noted in the table below:


	At March 31, 2022			At December 31, 2021
	Range of Inputs	Average (1)		Range of Inputs	Average (1)

CPRs	7.38% - 16.66%	9.42	%	7.90% - 17.35%	10.35	%
Discount Rates	8.10% - 15.18%	9.05	%	6.94% - 13.96%	7.97	%

To compute hypothetical sensitivities of the value of our single family MSRs to immediate adverse changes in key assumptions, we computed the impact of changes to CPRs and in discount rates as outlined below:


(dollars in thousands)	At March 31, 2022

Fair value of single family MSR	$	72,378
Expected weighted-average life (in years)	7.14
CPR
Impact on fair value of 25 basis points adverse change in interest rates	$	(2,208)
Impact on fair value of 50 basis points adverse change in interest rates	$	(4,909)
Discount rate
Impact on fair value of 100 basis points increase	$	(3,217)
Impact on fair value of 200 basis points increase	$	(6,187)

The changes in multifamily and SBA MSRs measured at the lower of amortized cost or fair value were as follows:


	Quarter Ended March 31,
(in thousands)	2022		2021

Beginning balance	$	39,415	$	35,774
Originations	1,576		5,196
Amortization	(1,712)		(1,344)
Ending balance	$	39,279	$	39,626