4) Securities

The amortized cost and estimated fair value of securities at March 31, 2020 and December 31, 2019 were as follows:


			Gross		Gross		Allowance		Estimated
	Amortized		Unrealized		Unrealized		for Credit		Fair
March 31, 2020	Cost		Gains		(Losses)		Losses		Value
	(Dollars in thousands)
Securities available-for-sale:
Agency mortgage-backed securities	$	244,968	$	6,868	$	—	$	—	$	251,836
U.S. Treasury		119,192		2,542		—		—		121,734
Total	$	364,160	$	9,410	$	—	$	—	$	373,570

			Gross		Gross		Estimated		Allowance
	Amortized		Unrealized		Unrealized		Fair		for Credit
March 31, 2020	Cost		Gains		(Losses)		Value		Losses
	(Dollars in thousands)
Securities held-to-maturity:
Agency mortgage-backed securities	$	270,211	$	6,746	$	(1)	$	276,956	$	—
Municipals - exempt from Federal tax		77,888		1,309		—		79,197		(55)
Total	$	348,099	$	8,055	$	(1)	$	356,153	$	(55)


			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
December 31, 2019	Cost		Gains		(Losses)		Value
	(Dollars in thousands)
Securities available-for-sale:
Agency mortgage-backed securities	$	283,598	$	934	$	(171)	$	284,361
U.S. Treasury		118,939		1,525		—		120,464
Total	$	402,537	$	2,459	$	(171)	$	404,825

			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
December 31, 2019	Cost		Gains		(Losses)		Value
	(Dollars in thousands)
Securities held-to-maturity:
Agency mortgage-backed securities	$	285,344	$	1,206	$	(968)	$	285,582
Municipals - exempt from Federal tax		81,216		1,313		(4)		82,525
Total	$	366,560	$	2,519	$	(972)	$	368,107

Securities with unrealized losses at March 31, 2020 and December 31, 2019, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position are as follows:


	Less Than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
March 31, 2020	Value		(Losses)		Value		(Losses)		Value		(Losses)
	(Dollars in thousands)
Securities held-to-maturity:
Agency mortgage-backed securities	$	—	$	—	$	1,183	$	(1)	$	1,183	$	(1)
Total	$	—	$	—	$	1,183	$	(1)	$	1,183	$	(1)


	Less Than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
December 31, 2019	Value		(Losses)		Value		(Losses)		Value		(Losses)
	(Dollars in thousands)
Securities available-for-sale:
Agency mortgage-backed securities	$	100,816	$	(105)	$	27,534	$	(66)	$	128,350	$	(171)
Total	$	100,816	$	(105)	$	27,534	$	(66)	$	128,350	$	(171)

Securities held-to-maturity:
Agency mortgage-backed securities	$	50,060	$	(178)	$	88,128	$	(790)	$	138,188	$	(968)
Municipals - exempt from Federal tax		1,556		(4)		—		—		1,556		(4)
Total	$	51,616	$	(182)	$	88,128	$	(790)	$	139,744	$	(972)

There were no holdings of securities of any one issuer, other than the U.S. Government and its sponsored entities, in an amount greater than 10% of shareholders’ equity. At March 31, 2020, the Company held 442 securities (128 available-for-sale and 314 held‑to‑maturity), of which one had fair value below amortized cost. At March 31, 2020, there were $1,183,000 of agency mortgage-backed securities held-to-maturity, carried with an unrealized loss for 12 months or more. The total unrealized loss for securities 12 months or more was $1,000 at March 31, 2020. The unrealized losses were due to higher interest rates. The issuers are of high credit quality and all principal amounts are expected to be paid when securities mature. The fair value is expected to recover as the securities approach their maturity date and/or market rates decline. The Company does not believe that it is more likely than not that the Company will be required to sell a security in an unrealized loss position prior to recovery in value. Therefore, the Company does not consider these debt securities to have credit related losses as of March 31, 2020.

The agency mortgage-backed securities and U.S. Treasury securities are either explicitly or implicitly guaranteed by the U.S. government, are highly rated by major credit rating agencies, and have a long history of no credit losses.Therefore, for those securities, we do not record expected credit losses.

The proceeds from sales of securities and the resulting gains and losses were as follows for the periods indicated:


	Three Months Ended
	March 31,
	2020		2019
	(Dollars in thousands)
Proceeds	$	26,513	$	—
Gross gains		100		—
Gross losses		—		—

The amortized cost and estimated fair values of securities as of March 31, 2020 are shown by contractual maturity below. The expected maturities will differ from contractual maturities if borrowers have the right to call or pre‑pay obligations with or without call or pre‑payment penalties. Securities not due at a single maturity date are shown separately.


	Available-for-sale
	Amortized		Estimated
	Cost		Fair Value
	(Dollars in thousands)
Due after 3 months through one year	$	74,668		75,759
Due after one through five years		44,524		45,975
Agency mortgage-backed securities		244,968		251,836
Total	$	364,160	$	373,570


	Held-to-maturity
	Amortized		Estimated
	Cost		Fair Value
	(Dollars in thousands)
Due after 3 months through one year	$	1,446	$	1,451
Due after one through five years		6,410		6,574
Due after five through ten years		36,178		36,812
Due after ten years		33,854		34,360
Agency mortgage-backed securities		270,211		276,956
Total	$	348,099	$	356,153

Securities with amortized cost of $41,408,000 and $32,773,000 as of March 31, 2020 and December 31, 2019 were pledged to secure public deposits and for other purposes as required or permitted by law or contract.

The table below presents a rollforward by major security type for the three months ended March 31, 2020 of the allowance for credit losses on debt securities held-to-maturity held at period end:


		Municipals
		(Dollars in thousands)
Beginning balance January 1, 2020	$	-
Impact of adopting Topic 326		58
Provision (credit) for credit loss		(3)
Ending balance March 31, 2020	$	55