The following table presents changes in mortgage servicing rights for the periods presented:


(dollars in thousands)	Mortgage Servicing Rights
Balance, January 1, 2021	$	11,865
Additions	717
Amortization	(2,082)
Balance, June 30, 2021	$	10,500

Balance, January 1, 2020	$	14,718
Additions	1,270
Amortization	(3,217)
Balance, June 30, 2020	$	12,771

Income generated as the result of new mortgage servicing rights is reported as gains on sales of loans and totaled $0.3 million and $0.7 million for the three and six months ended June 30, 2021, respectively, compared to $1.1 million and $1.3 million for the three and six months ended June 30, 2020, respectively.

Amortization of mortgage servicing rights totaled $0.9 million and $2.1 million for the three and six months ended June 30, 2021, respectively, compared to $1.7 million and $3.2 million for the three and six months ended June 30, 2020, respectively.

The following tables present the fair market value and key assumptions used in determining the fair market value of our mortgage servicing rights:


	Six Months Ended			Six Months Ended
(dollars in thousands)	June 30, 2021			June 30, 2020
Fair market value, beginning of period	$	12,003		$	15,820
Fair market value, end of period	10,755			13,060
Weighted average discount rate	9.6		%	9.6		%
Weighted average prepayment speed assumption	18.0		%	21.7		%

The gross carrying value and accumulated amortization related to our mortgage servicing rights are presented below:


	June 30, 2021						December 31, 2020
(dollars in thousands)	Gross Carrying Value		Accumulated Amortization		Net Carrying Value		Gross Carrying Value		Accumulated Amortization		Net Carrying Value

Mortgage servicing rights	$	71,626	$	(61,126)	$	10,500	$	70,909	$	(59,044)	$	11,865

Based on the mortgage servicing rights held as of June 30, 2021, estimated amortization expense for the remainder of fiscal year 2021, the next five succeeding fiscal years and all years thereafter are as follows:


(dollars in thousands)
Year Ending December 31,
2021 (remainder)	$	1,432
2022	2,446
2023	1,974
2024	1,596
2025	1,316
2026	1,092
Thereafter	644
Total	$	10,500