
	September 30, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Allowance for Credit Losses		Estimated Fair Value
U.S. Treasury notes and bonds	$	59,863	$	—	$	2,839	$	—	$	57,024
Mortgage-backed securities, residential	445,965		23		60,595		—		385,393
Obligations of states and political subdivisions	37,668		—		759		—		36,909
Corporate bonds and notes	25,750		—		4,285		—		21,465
SBA loan pools	55,709		54		1,979		—		53,784

Total	$	624,955	$	77	$	70,457	$	—	$	554,575


	December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Allowance for Credit Losses		Estimated Fair Value
U.S. Treasury notes and bonds	$	59,812	$	—	$	4,480	$	—	$	55,332
Mortgage-backed securities, residential	476,240		6		72,422		—		403,824

Obligations of states and political subdivisions	39,503		—		817		—		38,686
Corporate bonds and notes	25,750		—		5,081		—		20,669
SBA loan pools	67,787		75		2,380		—		65,482


Total	$	669,092	$	81	$	85,180	$	—	$	583,993


	September 30, 2024
	Amortized Cost		Unrecognized Gains		Unrecognized Losses		Estimated Fair Value		Allowance for Credit Losses
Obligations of states and political subdivisions	$	657	$	—	$	—	$	657	$	—


	December 31, 2023
	Amortized Cost		Unrecognized Gains		Unrecognized Losses		Estimated Fair Value		Allowance for Credit Losses
Obligations of states and political subdivisions	$	785	$	—	$	—	$	785	$	—

The amortized cost and estimated fair value of debt securities are shown below by expected maturity (in thousands). Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Securities not due at a single maturity date are shown separately.


	September 30, 2024
	Available for Sale				Held to Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Within one year	$	22,027	$	21,732	$	—	$	—
After one, but within five years	83,325		78,647		97		97
After five, but within ten years	17,779		14,875		560		560
After ten years	150		144		—		—
	123,281		115,398		657		657
Mortgage-backed securities, residential	445,965		385,393		—		—

SBA loan pools	55,709		53,784		—		—
Total	$	624,955	$	554,575	$	657	$	657

The following tables summarize the investment securities available for sale with unrealized losses as of September 30, 2024 and December 31, 2023 by aggregated major security type and length of time in a continuous unrealized loss position (in thousands):


	Less than 12 months				12 months or longer				Total
September 30, 2024	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury notes and bonds	$	—	$	—	$	57,024	$	2,839	$	57,024	$	2,839
Mortgage-backed securities, residential	—		—		383,865		60,595		383,865		60,595
Obligations of states and political subdivisions	—		—		36,474		759		36,474		759
Corporate bonds and notes	1,921		79		19,544		4,206		21,465		4,285
SBA loan pools	—		—		48,507		1,979		48,507		1,979

Total	$	1,921	$	79	$	545,414	$	70,378	$	547,335	$	70,457


	Less than 12 months				12 months or longer				Total
December 31, 2023	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury notes and bonds	$	—	$	—	$	55,332	$	4,480	$	55,332	$	4,480
Mortgage-backed securities, residential	—		—		402,986		72,422		402,986		72,422
Obligations of states and political subdivisions	17,891		241		20,686		576		38,577		817
Corporate bonds and notes	7,492		2,508		13,177		2,573		20,669		5,081
SBA loan pools	3,914		13		54,468		2,367		58,382		2,380
Total	$	29,297	$	2,762	$	546,649	$	82,418	$	575,946	$	85,180

Management assesses the decline in fair value of investment securities on a regular basis. Unrealized losses on debt securities may occur from current market conditions, increases in interest rates since the time of purchase, a structural change in an investment, volatility in earnings of a specific issuer, or deterioration in credit quality of the issuer. Management evaluates both qualitative and quantitative factors to assess whether potential credit losses exist. The following is a discussion of the credit quality characteristics of portfolio segments carrying material unrealized losses as of September 30, 2024.

As of September 30, 2024, the majority of the Corporation’s unrealized losses in available for sale investment securities related to mortgage-backed securities, issued by government-sponsored entities and agencies. Declines in fair value were attributable to changes in interest rates and illiquidity, not credit quality. The Corporation does not have the intent, and it is not likely to be required to, sell these securities prior to anticipated recovery. Due to affiliations with U.S. governmental agencies and or enterprises, the Corporation considers these obligations to carry zero loss estimates, and has not recorded an allowance for credit losses as of September 30, 2024.

The Corporation's corporate bonds and notes portfolio is comprised of subordinated debt issues of community and regional banks. Management considers the credit quality of these investments on an individual basis. Management reviewed the collectability of these securities, taking into consideration such factors as the financial condition of issuers, reported regulatory capital ratios of issuers, and credit ratings when available, among other pertinent factors. All corporate bond debt securities continue to accrue interest and make payments as expected with no defaults or deferrals on the part of the issuers. The decrease in market value is attributable to changes in interest rates. Therefore, the Corporation considers the potential credit risk of these issuers to be immaterial, and has not recorded an allowance for credit losses as of September 30, 2024.