	Three Months Ended September 30,						Nine Months Ended September 30,
Mortgage Servicing Rights	2019			2018			2019			2018
Beginning Balance	$	413,425		$	393,383		$	416,131		$	399,349
Additions		35,186			33,901			73,873			65,632
Purchases from an affiliate		123			516			845			2,124
Amortization		(22,503	)		(20,850	)		(64,618	)		(60,155	)
Ending Balance	$	426,231		$	406,950		$	426,231		$	406,950

Valuation Allowance
Beginning Balance	$	(12,642	)	$	(1,343	)	$	(4,322	)	$	(6,723	)
Decrease (increase)		(7,380	)		(366	)		(15,700	)		5,014
Ending Balance	$	(20,022	)	$	(1,709	)	$	(20,022	)	$	(1,709	)
Net balance	$	406,209		$	405,241		$	406,209		$	405,241

Servicing fees are included in “Management services, servicing fees and other” on the accompanying unaudited condensed consolidated statements of operations and were as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Servicing fees	$	26,526	$	26,143	$	78,134	$	77,367
Escrow interest and placement fees		6,518		5,395		17,505		12,229
Ancillary fees		3,955		3,410		11,270		6,611
Total	$	36,999	$	34,948	$	106,909	$	96,207

Newmark’s primary servicing portfolio at September 30, 2019 and December 31, 2018 was $59.2 billion and $57.1 billion, respectively. Also, Newmark is the named special servicer for a number of commercial mortgage-backed securitizations. Upon certain specified events (such as, but not limited to, loan defaults and loans assumptions), the administration of the loan is transferred to Newmark. Newmark’s special servicing portfolio at September 30, 2019 and December 31, 2018 was $2.1 billion and $2.9 billion, respectively.

The estimated fair value of the MSRs at September 30, 2019 and December 31, 2018 was $430.4 million and $451.9 million, respectively.

Fair values are estimated using a valuation model that calculates the present value of the future net servicing cash flows. The cash flows assumptions used are based on assumptions Newmark believes market participants would use to value the portfolio. Significant assumptions include estimates of the cost of servicing per loan, discount rate, earnings rate on escrow deposits and prepayment speeds. The discount rates used in measuring fair value for the nine months ended September 30, 2019 and the year ended December 31, 2018 were between 3.0% and 13.5% and varied based on investor type. An increase in discount rate of 100 basis points or 200 basis points would result in a decrease in fair value by $11.6 million and $22.7 million, respectively, at September 30, 2019 and by $12.4 million and $24.4 million, respectively, at December 31, 2018.