The following tables present amortized cost, gross unrealized gain and losses, and fair value of the available-for-sale investment securities and the amortized cost, net unrealized gains, carrying value, gross unrealized gains and losses and fair value of for held-to-maturity as of June 30, 2021 and December 31, 2020:

(1)

Net unrealized gains on held-to-maturity securities represents the net unrealized gains /(losses) on previously available-for-sale securities transferred to held-to-maturity at fair value and is being amortized through accumulated other comprehensive income over the remaining life of the securities.

(2)	Unrecognized gains and losses of held-to-maturity securities are not reflected in the financial statements, as they represent fair value fluctuations from the date of the security is designated as held-to-maturity.


	December 31, 2020
	Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value
Available-for-sale
U.S. Treasury and agencies	$	5,926	$	—	$	(19)	$	5,907
Obligations of state and political agencies		148,491		5,282		—		153,773
Mortgage backed securities
Residential agency		303,760		3,395		(436)		306,719
Commercial		89,300		5,678		—		94,978
Asset backed securities		109		6		—		115
Corporate bonds		30,552		388		(90)		30,850
Total available-for-sale investment securities	$	578,138	$	14,749	$	(545)	$	592,342

On April 1, 2021, the Company transferred its debt securities consisting of obligations of state and political agencies with a fair value of $149.2 million and a net unrealized gain of $1.3 million from available-for-sale to held-to-maturity.

Gross unrealized losses on investment securities and the fair value of the related securities aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of June 30, 2021 and December 31, 2020, were as follows:


	June 30, 2021
	Less than 12 Months				Over 12 Months				Total
	Unrealized		Fair		Unrealized		Fair		Unrealized		Fair
(dollars in thousands)	Losses		Value		Losses		Value		Losses		Value
Available-for-sale
U.S. Treasury and agencies	$	—	$	—	$	—	$	—	$	—	$	—
Mortgage backed securities
Residential agency		(6,022)		322,584		—		—		(6,022)		322,584
Commercial		—		—		—		—		—		—
Asset backed securities		—		—		—		2		—		2
Corporate bonds		(264)		9,736		—		—		(264)		9,736
Total available-for-sale investment securities	$	(6,286)	$	332,320	$	—	$	2	$	(6,286)	$	332,322
Held-to-maturity
Obligations of state and political agencies	$	(5)	$	5,996	$	—	$	—	$	(5)	$	5,996
Total held-to-maturity investment securities		(5)		5,996		—		—		(5)		5,996
Total investment securities	$	(6,291)	$	338,316		—		2		(6,291)		338,318


	December 31, 2020
	Less than 12 Months				Over 12 Months				Total
	Unrealized		Fair		Unrealized		Fair		Unrealized		Fair
(dollars in thousands)	Losses		Value		Losses		Value		Losses		Value
Available-for-sale
U.S. Treasury and agencies	$	(10)	$	4,509	$	(9)	$	1,309	$	(19)	$	5,818
Obligations of state and political agencies		—		—		—		—		—		—
Mortgage backed securities
Residential agency		(432)		68,494		(4)		2,356		(436)		70,850
Commercial		—		—		—		—		—		—
Asset backed securities		—		—		—		2		—		2
Corporate bonds		(90)		16,454		—		—		(90)		16,454
Total available-for-sale investment securities	$	(532)	$	89,457	$	(13)	$	3,667	$	(545)	$	93,124

For all of the above investment securities, the unrealized losses were generally due to changes in interest rates and unrealized losses were considered to be temporary as the fair value is expected to recover as the securities approach their maturity dates. The Company evaluates securities for other-than-temporary impairment, or OTTI, on a quarterly basis, at a minimum, and more frequently when economic or market concerns warrant such evaluation. In estimating OTTI losses, consideration is given to the severity and duration of the impairment; the financial condition and near-term prospects of the issuer, which for debt securities, considers external credit ratings and recent downgrades; and the intent and ability of the Company to hold the security for a period of time sufficient for a recovery in value.

For the three and six months ended June 30, 2021 and 2020, the Company did not recognize OTTI losses on its investment securities.

The following table presents amortized cost and fair value of available-for-sale and held-to-maturity investment securities as of June 30, 2021, by contractual maturity:


	Held-to-maturity				Available-for-sale
	Carrying		Fair		Amortized		Fair
(dollars in thousands)	Value		Value		Cost		Value
Due within one year or less	$	5,141	$	5,142	$	—	$	—
Due after one year through five years		28,706		28,745		3,001		3,100
Due after five years through ten years		76,714		77,812		86,721		89,886
Due after 10 years		35,755		36,586		559,605		558,560
Total investment securities	$	146,316	$	148,285	$	649,327	$	651,546

Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

Investment securities with a total carrying value of $171.4 million and $160.8 million were pledged as of June 30, 2021 and December 31, 2020, respectively, to secure public deposits and for other purposes required or permitted by law.

Proceeds from the sale or call of available-for-sale investment securities, for the three and six months ended June 30, 2021 and 2020, are displayed in the table below:


	Three months ended				Six months ended
	June 30,				June 30,
(dollars in thousands)	2021		2020		2021		2020
Proceeds	$	—	$	35,505	$	13,189	$	39,505
Realized gains		—		1,294		114		1,294
Realized losses		—		—		—		—

As of June 30, 2021 and December 31, 2020, the carrying value of the Company’s Federal Reserve stock and Federal Home Loan Bank of Des Moines, or FHLB, stock was as follows:


	June 30,		December 31,
(dollars in thousands)	2021		2020
Federal Reserve	$	2,675	$	2,675
FHLB		3,839		3,090

These securities can only be redeemed or sold at their par value and only to the respective issuing institution or to another member institution. The Company records these non-marketable equity securities as a component of other assets and periodically evaluates these securities for impairment. Management considers these non-marketable equity securities to be long-term investments. Accordingly, when evaluating these securities for impairment, management considers the ultimate recoverability of the par value rather than recognizing temporary declines in value.

Visa Class B Restricted Shares

In 2008, the Company received Visa Class B restricted shares as part of Visa’s initial public offering. These shares are transferable only under limited circumstances until they can be converted into the publicly traded Class A common shares. This conversion will not occur until the settlement of certain litigation which will be indemnified by Visa members, including the Company. Visa funded an escrow account from its initial public offering to settle these litigation claims. Should this escrow account be insufficient to cover these litigation claims, Visa is entitled to fund additional amounts to the escrow account by reducing each member bank’s Class B conversion ratio to unrestricted Class A shares. As of June 30, 2021, the conversion ratio was 1.6228. Based on the existing transfer restriction and the uncertainty of the outcome of the Visa litigation mentioned above, the 6,924 Class B shares (11,236 Class A equivalents) that the Company owned as of June 30, 2021 and December 31, 2020, are carried at a zero cost basis.