
	December 31, 2020
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Available-for-Sale Debt Securities
U.S. Treasury securities and obligations of U.S. government agencies	$	8,250	$	528	$	(1)	$	8,777
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	1,038,437		23,457		(1,240)		1,060,654
Private mortgage-backed securities and collateralized mortgage obligations	89,284		2,131		(210)		91,205
Collateralized loan obligations	202,563		279		(647)		202,195
Obligations of state and political subdivisions	33,005		2,321		—		35,326
Totals	$	1,371,539	$	28,716	$	(2,098)	$	1,398,157

Held-to-Maturity Debt Securities
Mortgage-backed securities of U.S. government-sponsored entities	$	184,484	$	7,818	$	(123)	$	192,179


Totals	$	184,484	$	7,818	$	(123)	$	192,179


	December 31, 2019
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Available-for-Sale Debt Securities
U.S. Treasury securities and obligations of U.S. government agencies	$	9,914	$	204	$	(4)	$	10,114
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	604,934		5,784		(1,511)		609,207
Private mortgage-backed securities and collateralized mortgage obligations	56,005		1,561		(5)		57,561
Collateralized loan obligations	239,364		7		(1,153)		238,218
Obligations of state and political subdivisions	30,548		1,208		(1)		31,755
Totals	$	940,765	$	8,764	$	(2,674)	$	946,855

Held-to-Maturity Debt Securities
Mortgage-backed securities of U.S. government-sponsored entities	$	261,369	$	2,717	$	(1,873)	$	262,213


Totals	$	261,369	$	2,717	$	(1,873)	$	262,213

Proceeds from sales of debt securities during 2020 were $96.7 million, with gross gains of $2.4 million and gross losses of $1.3 million. Proceeds from sales of debt securities during 2019 were $202.7 million with gross gains of $2.9 million and gross losses of $1.8 million. Proceeds from sales of debt securities during 2018 were $64.4 million with gross gains of $0.2 million and gross losses of $0.7 million. Also included in “Securities gains (losses) net” are increases of $0.1 million and $0.2 million in 2020 and 2019, respectively, and a decrease of $0.1 million in 2018, in the value of an investment in shares of a mutual fund that invests in CRA-qualified debt securities.

The amortized cost and fair value of securities at December 31, 2020, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because prepayments of the underlying collateral for these securities may occur, due to the right to call or repay obligations with or without call or prepayment penalties. Securities not due at a single maturity date are shown separately.


	Held-to-Maturity				Available-for-Sale
(In thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than one year	$	—	$	—	$	35	$	35
Due after one year through five years	—		—		11,305		11,929
Due after five years through ten years	—		—		8,590		9,323
Due after ten years	—		—		21,325		22,816
	—		—		41,255		44,103
Mortgage-backed securities of U.S. government-sponsored entities	184,484		192,179		1,038,437		1,060,654
Private mortgage-backed securities and collateralized mortgage obligations	—		—		89,284		91,205
Collateralized loan obligations	—		—		202,563		202,195
Totals	$	184,484	$	192,179	$	1,371,539	$	1,398,157

The estimated fair value of a security is determined based on market quotations when available or, if not available, by using quoted market prices for similar securities, pricing models or discounted cash flows analyses, using observable market data where available. The tables below indicate, at December 31, 2020, the fair value of available-for-sale debt securities with unrealized losses for which no allowance for credit losses has been recorded, and at December 31, 2019, the fair value of available-for-sale and held-to-maturity debt securities with unrealized losses for which no allowance has been recorded.


	December 31, 2020
	Less than 12 months				12 months or longer				Total
(In thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. government agencies	$	—	$	—	$	256	$	(1)	$	256	$	(1)
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	203,405		(1,218)		569		(22)		203,974		(1,240)
Private mortgage-backed securities and collateralized mortgage obligations	23,997		(210)		—		—		23,997		(210)
Collateralized loan obligations	104,697		(102)		72,513		(545)		177,210		(647)

Totals	$	332,099	$	(1,530)	$	73,338	$	(568)	$	405,437	$	(2,098)


	December 31, 2019
	Less than 12 months				12 months or longer				Total
(In thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. government agencies	$	758	$	(4)	$	—	$	—	$	758	$	(4)
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	220,057		(1,461)		104,184		(1,923)		324,241		(3,384)
Private mortgage-backed securities and collateralized mortgage obligations	2,978		(5)		—		—		2,978		(5)
Collateralized loan obligations	88,680		(570)		110,767		(583)		199,447		(1,153)
Obligations of state and political subdivisions	515		(1)		—		—		515		(1)
Totals	$	312,988	$	(2,041)	$	214,951	$	(2,506)	$	527,939	$	(4,547)

At December 31, 2020, the Company had unrealized losses of $1.2 million on mortgage-backed securities and collateralized mortgage obligations issued by government-sponsored entities having a fair value of $204.0 million. These securities are either explicitly or implicitly guaranteed by the U.S. Government and have a long history of no credit losses. The implied government guarantee of principal and interest payments and the high credit rating of the portfolio provide sufficient basis for the current expectation that there is no risk of loss if default were to occur. Based on the assessment of all relevant factors, the Company believes that the unrealized loss positions on these debt securities are a function of changes in investment spreads and interest rate movements and not changes in credit quality, and expects to recover the entire amortized cost basis of these securities. Therefore, at December 31, 2020, no allowance for credit losses has been recorded.

At December 31, 2020, the Company had $0.6 million of unrealized losses in uncapped 3-month LIBOR floating rate collateralized loan obligations (“CLOs”) having a fair value of $177.2 million. CLOs are special purpose vehicles and those in which the Company has acquired nearly all first-lien, broadly syndicated corporate loans across a diversified band of industries while providing support to senior tranche investors. As of December 31, 2020, all positions held by the Company are in AAA and AA tranches, with average credit support of 35% and 25%, respectively. The Company evaluates the securities for potential credit losses by modeling expected loan-level defaults, recoveries, and prepayments for each CLO security. Based on the assessment of all relevant factors, the Company believes that the unrealized loss positions on these debt securities are a function of changes in investment spreads and interest rate movement and not changes in credit quality, and expects to recover the entire amortized cost basis of these securities. Therefore, at December 31, 2020, no allowance for credit losses has been recorded.

At December 31, 2020, the Company had $0.2 million of unrealized losses on private label residential and commercial mortgage-backed securities and collateralized mortgage obligations having a fair value of $24.0 million. The collateral underlying these mortgage investments is primarily residential real estate. The securities have average credit support of 22%. Based on the assessment of all relevant factors, the Company believes that the unrealized loss positions on these debt securities are a function of changes in investment spreads and interest rate movements and not changes in credit quality, and expects to recover the entire amortized cost basis of these securities. Therefore, at December 31, 2020, no allowance for credit losses has been recorded.

All HTM debt securities are issued by government-sponsored entities, which are either explicitly or implicitly guaranteed by the U.S. government and have a long history of no credit losses. While the potential for default on these securities may be something greater than zero, the long history with no credit losses, the implied government guarantee of principal and interest payments and the high credit rating of the HTM portfolio provide sufficient basis for the current expectation that there is no risk of loss if default were to occur. Despite the emergence of significant market changes and increasing degrees of uncertainty that occurred in the U.S. economy in 2020, there has to date been no specific impact on the agencies or changes in the nature or quality of the guarantee they provide. As a result, as of December 31, 2020, no allowance for credit losses has been recorded.

Included in other assets at December 31, 2020 is $33.9 million of Federal Home Loan Bank and Federal Reserve Bank stock stated at par value. The Company has not identified events or changes in circumstances which may have a significant adverse effect on the fair value of these cost method investment securities. Accrued interest receivable on AFS and HTM debt securities of $3.2 million and $0.4 million at December 31, 2020, respectively, and $3.8 million and $0.6 million at December 31, 2019, respectively, is included in other assets. Also included in other assets is a $6.5 million investment in a mutual fund carried at fair value.