Securities Available for Sale and Held to Maturity

9 Months Ended

Sep. 30, 2025

Investments, Debt and Equity Securities [Abstract]

Securities Available for Sale and Held to Maturity

Note 3 – Securities Available for Sale and Held to Maturity

The following tables are a summary of the amortized cost and estimated fair value of securities available for sale and held to maturity at September 30, 2025 and December 31, 2024 ($ in thousands):

	Securities Available for Sale									Securities Held to Maturity
September 30, 2025	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. Treasury securities	$	204,757	$	3,512	$	—		$	208,269	$	30,421	$	114	$	—		$	30,535
U.S. Government agency    obligations		70,756		575		(796	)		70,535		—		—		—			—
Mortgage-backed securities
Residential mortgage pass-    through securities
Guaranteed by GNMA		37,815		92		(2,101	)		35,806		14,353		5		(445	)		13,913
Issued by FNMA and    FHLMC		1,109,332		30,057		(12,458	)		1,126,931		384,625		345		(9,297	)		375,673
Other residential mortgage-    backed securities
Issued or guaranteed by    FNMA, FHLMC or    GNMA		—		—		—			—		103,041		—		(4,794	)		98,247
Commercial mortgage-    backed securities
Issued or guaranteed by    FNMA, FHLMC or    GNMA		362,283		10,948		(527	)		372,704		736,019		71		(20,722	)		715,368
Total	$	1,784,943	$	45,184	$	(15,882	)	$	1,814,245	$	1,268,459	$	535	$	(35,258	)	$	1,233,736

	Securities Available for Sale									Securities Held to Maturity
December 31, 2024	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. Treasury Securities	$	203,524	$	548	$	(1,403	)	$	202,669	$	29,842	$	1	$	(522	)	$	29,321
U.S. Government agency    obligations		41,194		—		(2,387	)		38,807		—		—		—			—
Mortgage-backed securities
Residential mortgage pass-    through securities
Guaranteed by GNMA		31,365		3		(2,957	)		28,411		16,218		—		(844	)		15,374
Issued by FNMA and    FHLMC		1,091,122		1,610		(22,194	)		1,070,538		423,372		94		(23,853	)		399,613
Other residential mortgage-    backed securities
Issued or guaranteed by    FNMA, FHLMC or    GNMA		—		—		—			—		123,685		—		(8,004	)		115,681
Commercial mortgage-    backed securities
Issued or guaranteed by    FNMA, FHLMC or    GNMA		352,332		827		(1,050	)		352,109		742,268		3		(43,153	)		699,118
Total	$	1,719,537	$	2,988	$	(29,991	)	$	1,692,534	$	1,335,385	$	98	$	(76,376	)	$	1,259,107

During 2022, Trustmark reclassified a total of $766.0 million of securities available for sale to securities held to maturity. At the date of these transfers, the net unrealized holding loss on the available for sale securities totaled $91.9 million ($68.9 million, net of tax). The securities were transferred at fair value, which became the cost basis for the securities held to maturity. The net unrealized holding loss will be amortized over the remaining life of the securities as a yield adjustment in a manner consistent with the amortization or accretion of the original purchase premium or discount on the associated security. There were no gains or losses recognized as a result of these transfers. At September 30, 2025, the net unamortized, unrealized loss on transferred securities included in accumulated other comprehensive income (loss) in the accompanying consolidated balance sheets totaled $38.9 million compared to $46.6 million at December 31, 2024.

ACL on Securities

Securities Available for Sale

Quarterly, Trustmark evaluates if any security has a fair value less than its amortized cost. Once these securities are identified, in order to determine whether a decline in fair value resulted from a credit loss or other factors, Trustmark performs further analysis. If Trustmark determines that a credit loss exists, the credit portion of the allowance is measured by a discounted cash flow (DCF) analysis using the effective interest rate as of the security’s purchase date. The amount of credit loss recorded by Trustmark is limited to the amount by which the amortized cost exceeds the fair value. The DCF analysis utilizes contractual maturities, as well as third-party credit ratings and cumulative default rates published annually by Moody’s Investor Service (Moody’s).

At both September 30, 2025 and December 31, 2024, the results of the analysis did not identify any securities that warranted DCF analysis, and no credit loss was recognized on any of the securities available for sale.

Accrued interest receivable is excluded from the estimate of credit losses for securities available for sale. At September 30, 2025, accrued interest receivable totaled $5.9 million for securities available for sale compared to $5.0 million December 31, 2024 and was reported in other assets on the accompanying consolidated balance sheet.

Securities Held to Maturity

At September 30, 2025 and December 31, 2024, Trustmark identified no securities held to maturity with the potential for credit loss exposure. After applying appropriate analysis, the total amount of current expected credit losses was zero at September 30, 2025 and December 31, 2024. No reserve was recorded at either September 30, 2025 or December 31, 2024.

Accrued interest receivable is excluded from the estimate of credit losses for securities held to maturity. At September 30, 2025, accrued interest receivable totaled $2.3 million for securities held to maturity compared to $2.4 million at December 31, 2024 and was reported in other assets on the accompanying consolidated balance sheet.

At both September 30, 2025 and December 31, 2024, Trustmark had no securities held to maturity that were past due 30 days or more as to principal or interest payments. Trustmark had no securities held to maturity classified as nonaccrual at September 30, 2025 and December 31, 2024.

Trustmark monitors the credit quality of securities held to maturity on a monthly basis through credit ratings. The following table presents the amortized cost of Trustmark’s securities held to maturity by credit rating, as determined by Moody’s, at September 30,2025 and December 31, 2024 ($ in thousands):

	September 30, 2025		December 31, 2024
Aaa	$	52,831	$	1,335,385
Aa1 to Aa3		1,215,628		—
Total	$	1,268,459	$	1,335,385

The tables below include securities with gross unrealized losses for which an allowance for credit losses has not been recorded segregated by length of impairment at September 30, 2025 and December 31, 2024 ($ in thousands):

	Less than 12 Months					12 Months or More					Total
September 30, 2025	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
U.S. Government agency obligations	$	25,624	$	(313	)	$	19,015	$	(483	)	$	44,639	$	(796	)
Mortgage-backed securities
Residential mortgage pass-through    securities
Guaranteed by GNMA		1,212		(23	)		29,230		(2,523	)		30,442		(2,546	)
Issued by FNMA and FHLMC		284,623		(600	)		228,922		(21,155	)		513,545		(21,755	)
Other residential mortgage-backed    securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		—		—			98,247		(4,794	)		98,247		(4,794	)
Commercial mortgage-backed securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		—		—			779,016		(21,249	)		779,016		(21,249	)
Total	$	311,459	$	(936	)	$	1,154,430	$	(50,204	)	$	1,465,889	$	(51,140	)
December 31, 2024
U.S. Treasury Securities	$	123,277	$	(1,925	)	$	—	$	—		$	123,277	$	(1,925	)
U.S. Government agency obligations		38,807		(2,387	)		—		—			38,807		(2,387	)
Mortgage-backed securities
Residential mortgage pass-through    securities
Guaranteed by GNMA		15,802		(293	)		27,803		(3,508	)		43,605		(3,801	)
Issued by FNMA and FHLMC		981,747		(13,848	)		237,487		(32,199	)		1,219,234		(46,047	)
Other residential mortgage-backed    securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		—		—			115,681		(8,004	)		115,681		(8,004	)
Commercial mortgage-backed securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		164,971		(536	)		767,566		(43,667	)		932,537		(44,203	)
Total	$	1,324,604	$	(18,989	)	$	1,148,537	$	(87,378	)	$	2,473,141	$	(106,367	)

The unrealized losses shown above are due to increases in market rates over the yields available at the time of purchase of the underlying securities and not credit quality. Trustmark does not intend to sell these securities and it is more likely than not that Trustmark will not be required to sell the investments before recovery of their amortized cost bases, which may be at maturity.

Securities Gains and Losses

Realized gains and losses are determined using the specific identification method and are included in noninterest income (loss) as securities gains (losses), net. For the periods presented, gross realized losses as a result of calls and dispositions of securities, as well as any associated proceeds, are shown below ($ in thousands). There were no gross realized gains during the periods presented.

	Three Months Ended September 30,				Nine Months Ended September 30,
Available for Sale	2025		2024		2025		2024
Proceeds from calls and sales of securities	$	—	$	—	$	—	$	1,378,272
Gross realized (losses)		—		—		—		(182,792	)

During the second quarter of 2024, Trustmark restructured its investment securities portfolio by selling $1.561 billion of available for sale securities with an average yield of 1.36%, which generated a loss of $182.8 million ($137.1 million, net of taxes) and was recorded to noninterest income (loss) in securities gains (losses), net. Proceeds from the sale were used to purchase $1.378 billion of available for sale securities with an average yield of 4.85%.

Securities Pledged

Securities with a carrying value of $1.749 billion and $1.910 billion at September 30, 2025 and December 31, 2024, respectively, were pledged to collateralize public deposits and securities sold under repurchase agreements and for other purposes as permitted by law. At both September 30, 2025 and December 31, 2024, none of these securities were pledged under the Federal Reserve Discount Window program to provide additional contingency funding capacity.

Contractual Maturities

The amortized cost and estimated fair value of securities available for sale and held to maturity at September 30, 2025, by contractual maturity, are shown below ($ in thousands). Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	Securities Available for Sale				Securities Held to Maturity
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Due in one year or less	$	35,927	$	36,122	$	—	$	—
Due after one year through five years		39,643		40,166		30,421		30,535
Due after five years through ten years		199,943		202,516		—		—
		275,513		278,804		30,421		30,535
Mortgage-backed securities		1,509,430		1,535,441		1,238,038		1,203,201
Total	$	1,784,943	$	1,814,245	$	1,268,459	$	1,233,736