The following is the amortized cost and fair value of investment securities held-to-maturity:

The following is the amortized cost and fair value of investment securities available-for-sale:

* The Company’s government-sponsored entities holdings are comprised of debt securities offered by Federal Home Loan Mortgage Corporation (“FHLMC”) or Freddie Mac, Federal National Mortgage Association (“FNMA”) or Fannie Mae, FHLB, and Federal Farm Credit Banks (“FFCB”).

** All of the mortgage-backed securities are issued by government-sponsored entities; there are no private-label holdings. Also included in the Company’s government-sponsored entities are debt securities offered by the Small Business Administration (“SBA”), which have the full faith and credit backing of the United States Government.

The following is the amortized cost and carrying value of other investment securities:



	Carrying
(Dollars in thousands)	Value
December 31, 2020:
Federal Home Loan Bank stock	$	15,083
Federal Reserve Bank stock		129,871
Investment in unconsolidated subsidiaries		4,941
Other nonmarketable investment securities		10,548
	$	160,443
December 31, 2019:
Federal Home Loan Bank stock	$	43,044
Investment in unconsolidated subsidiaries		3,563
Other nonmarketable investment securities		2,517
	$	49,124

The Company’s other investment securities consist of non-marketable equity securities that have no readily determinable market value. Accordingly, when evaluating these securities for impairment, management considers the ultimate recoverability of the par value rather than recognizing temporary declines in value. As of December 31, 2020, the Company has determined that there was no impairment on its other investment securities.

The amortized cost and fair value of debt and equity securities at December 31, 2020 by contractual maturity are detailed below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties.


	Securities				Securities
	Held-to-maturity				Available-for-sale
	Amortized		Fair		Amortized		Fair
(Dollars in thousands)	Cost		Value		Cost		Value
Due in one year or less	$	—	$	—	$	9,669	$	9,698
Due after one year through five years		—		—		80,846		83,586
Due after five years through ten years		88,735		89,007		525,547		539,905
Due after ten years		866,807		868,176		2,651,975		2,697,483
	$	955,542	$	957,183	$	3,268,037	$	3,330,672

The following table summarizes information with respect to sales of available-for-sale securities:


	Year Ended December 31,
(Dollars in thousands)	2020		2019		2018
Securities Available-for-sale:
Sale proceeds	$	100,754	$	242,733	$	73,054
Gross realized gains		662		6,030		31
Gross realized losses		(612)		(3,319)		(686)
Net realized gain (loss)	$	50	$	2,711	$	(655)

There was a net realized gain of $50,000 on the sale of securities for the year ended December 31, 2020, compared to a net realized gain of $2.7 million for the year ended December 31, 2019 and a net realized loss of $655,000 for the year ended December 31, 2018. The net realized gain of $2.7 million for the year ended December 31, 2019 includes net realized gains totaling $5.4 million from the sale of VISA Class B shares in the first and second quarters of 2019. If the gains from the VISA Class B share are excluded in 2019, the Company would have had a net realized loss of $2.7 million on the sale of available-for-sale securities for the year ended December 31, 2019.

There were no sales of held-to-maturity securities for years ended December 31, 2020, 2019 or 2018.

The Company had 86 securities with gross unrealized losses at December 31, 2020. Information pertaining to securities with gross unrealized losses at December 31, 2020 and 2019, aggregated by investment category and length of time that individual securities have been in a continuous loss position follows:


	Less Than				Twelve Months
	Twelve Months				or More
	Gross				Gross
	Unrealized		Fair		Unrealized		Fair
(Dollars in thousands)	Losses		Value		Losses		Value
December 31, 2020:
Securities Held-to-maturity
Mortgage-backed securities	$	1,123	$	240,591	$	—	$	—
	$	1,123	$	240,591	$	—	$	—
Securities Available-for-sale
Government-sponsored entities debt	$	642	$	24,358	$	—	$	—
State and municipal obligations		27		8,620		—		—
Mortgage-backed securities		2,475		509,319		1,021		105,125
	$	3,144	$	542,297	$	1,021	$	105,125
December 31, 2019:
Securities Available-for-sale
Government-sponsored entities debt	$	—	$	—	$	—	$	—
State and municipal obligations		764		42,070		—		—
Mortgage-backed securities		2,422		461,658		1,353		141,982
	$	3,186	$	503,728	$	1,353	$	141,982

Management evaluates securities for impairment where there has been a decline in fair value below the amortized cost basis of a security to determine whether there is a credit loss associated with the decline in fair value on at least a quarterly basis, and more frequently when economic or market concerns warrant such evaluation. Credit losses are calculated individually, rather than collectively, using a discounted cash flow method, whereby Management compares the present value of expected cash flows with the amortized cost basis of the security. The credit loss component would be recognized through the provision for credit losses. Consideration is given to (1) the financial condition and near-term prospects of the issuer including looking at default and delinquency rates, (2) the outlook for receiving the contractual cash flows of the investments, (3) the length of time and the extent to which the fair value has been less than cost, (4) our intent and ability to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value or for a debt security whether it is more-likely-than-not that we will be required to sell the debt security prior to recovering its fair value, (5) the anticipated outlook for changes in the general level of interest rates, (6) credit ratings, (7) third party guarantees, and (8) collateral values. In analyzing an issuer’s financial condition, management considers whether the securities are issued by the federal government or its agencies, whether downgrades by bond rating agencies have occurred, the results of reviews of the issuer’s financial condition, and the issuer’s anticipated ability to pay the contractual cash flows of the investments. The Company performed an analysis that determined that the following securities have a zero expected credit loss: U.S. Treasury Securities, Agency-Backed Securities including securities issued by GNMA, FNMA, FHLB, FFCB and SBA. All of the U.S. Treasury and Agency-Backed Securities have the full faith and credit backing of the United State Government or one of its agencies. Municipal securities and all other securities that do not have a zero expected credit loss are evaluated quarterly to determine whether there is a credit loss associated with a decline in fair value. All debt securities in an unrealized loss position as of December 31, 2020 continue to perform as scheduled and we do not believe that there is a credit loss or that a provision for credit losses is necessary. Also, as part of our evaluation of our intent and ability to hold investments for a period of time sufficient to allow for any anticipated recovery in the market, we consider our investment strategy, cash flow needs, liquidity position, capital adequacy and interest rate risk position. We do not currently intend to sell the securities within the portfolio and it is not more-likely-than-not that we will be required to sell the debt securities. See Note 1—Summary of Significant Account Policies for further discussion

Management continues to monitor all of our securities with a high degree of scrutiny. There can be no assurance that we will not conclude in future periods that conditions existing at that time indicate some or all of its securities may be sold or would require a charge to earnings as a provision for credit losses in such periods.

At December 31, 2020 and 2019, investment securities with a carrying value of $2.1 billion and $726.1 million, respectively, were pledged to secure public funds deposits and for other purposes required and permitted by law. At

December 31, 2020 and 2019, the carrying amount of the securities pledged to collateralize repurchase agreements was $515.9 million and $242.2 million, respectively.