The following table shows a comparison of amortized cost and fair values of investment securities at December 31, 2021 and 2020:

Proceeds from sales of available-for-sale securities and the realized gains and losses for the years ended December 31, 2021 and 2020 are as follows:

The following table shows the Corporation’s securities with gross unrealized and unrecognized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized position, at December 31, 2021 and 2020:

Each of these investment securities has been evaluated for OTTI. In performing a detailed cash flow analysis of each investment security, the Bank works with an independent third party to estimate expected cash flows and assist with the evaluation of OTTI. The cash flow analyses performed included the following assumptions:

There were no other than temporary impairment charges related to credit losses or sales of these securities during the years ended December 31, 2021 or 2020.

Management performs due diligence on the third-party processes and has an adequate understanding of the analysis, assumptions and methodology used by the third party to prepare the fair value determination and the OTTI evaluation. Management reviews the qualifications of the third party and believes they are qualified to provide the analysis and pricing determinations. Quarterly, management reviews the third party’s detailed assumptions and analyzes its projected discounted present value results for reasonableness and consistency with the trend of prior projections. Annually, management performs stress tests of the assumptions used in the third party models and performs back tests of the assumptions and prepayment projections to validate the impairment model results. As a result of its due diligence process, the fair value presented and the OTTI recognized are appropriate. A total of $3.0 million in impairment losses was realized during the time period 2009 through 2011 on the CDO portfolio remaining at December 31, 2021. Due to the prior credit impairment, the securities in this portfolio have continued to be evaluated to determine whether any additional OTTI has occurred. Based on management’s review of the third-party evaluations, there were no material differences in the relative valuations between December 31, 2021 and December 31, 2020.

Due to the duration and market value decline in the pooled trust preferred securities held in our portfolio, we performed more extensive testing on these securities for purposes of evaluating whether or not OTTI has occurred.

The market for these securities as of December 31, 2021 was not active and markets for similar securities were also not active. The inactivity was evidenced first by a significant widening of the bid-ask spread in the brokered markets in which these securities trade and then by a significant decrease in the volume of trades relative to historical levels. The new issue market is also inactive, as no new CDOs have been issued since 2007. There are currently very few market participants who are willing to effect transactions in these securities. The market values for these securities, or any securities other than those issued or guaranteed by the U.S. Department of the Treasury (the “Treasury”), are very depressed relative to historical levels. Therefore, in the current market, a low market price for a particular bond may only provide evidence of stress in the credit markets in general rather than being an indicator of credit problems with a particular issue. Given the conditions in the current debt markets and the absence of observable transactions in the secondary and new issue markets, management has determined that (a) the few observable transactions and market quotations that are available are not reliable for the purpose of obtaining fair value at December 31, 2021, (b) an income valuation approach technique (i.e. present value) that maximizes the use of relevant unobservable inputs and minimizes the use of observable inputs will be equally or more representative of fair value than a market approach, and (c) the CDO segment is appropriately classified within Level 3 of the valuation hierarchy because management determined that significant adjustments were required to determine fair value at the measurement date.

Management utilizes an independent third party to prepare both the evaluations of OTTI and the fair value determinations for the CDO portfolio. Management does not believe that there were any material differences in the OTTI evaluations and pricing between December 31, 2020 and December 31, 2021.

The following table presents a cumulative roll-forward of the amount of OTTI charges related to credit losses which have been recognized in earnings for the trust preferred securities in the CDO portfolio held and not intended to be sold for the years ended December 31, 2021 and 2020:



(in thousands)	2021		2020
Balance of credit-related OTTI at January 1	$	2,244	$	2,446
Reduction for increases in cash flows expected to be collected		(201)		(202)
Balance of credit-related OTTI at December 31	$	2,043	$	2,244

The amortized cost and estimated fair value of securities by contractual maturity at December 31, 2021 are shown in the following table. Actual maturities will differ from contractual maturities because the issuers of the securities may have the right to call or prepay obligations with or without call or prepayment penalties.



(in thousands)	Amortized Cost		Fair Value
Contractual Maturity
Available for sale:
Due after one year through five years	$	9,398	$	9,501
Due after five years through ten years		19,124		19,044
Due after ten years		72,128		68,620
		100,650		97,165
Residential mortgage-backed agencies		49,630		48,661
Commercial mortgage-backed agencies		51,694		50,868
Collateralized mortgage obligations		93,018		90,077
Total available for sale	$	294,992	$	286,771
Held to Maturity:
Due after ten years	$	20,169	$	28,921
		20,169		28,921
Residential mortgage-backed agencies		30,634		30,847
Commercial mortgage-backed agencies		5,456		5,601
Collateralized mortgage obligations		—		—
Total held to maturity	$	56,259	$	65,369

At December 31, 2021 and 2020, investment securities with a value of $158.7 million and $137.1 million, respectively, were pledged as permitted or required to secure public deposits, for securities sold under agreements to repurchase as required or permitted by law and as collateral for borrowing capacity.