Shareholders' Equity (Tables)

3 Months Ended

Mar. 31, 2025

Stockholders' Equity Note [Abstract]

Table of Actual Regulatory Capital Amounts and Ratios

The following table provides Trustmark’s and TNB’s actual regulatory capital amounts and ratios under regulatory capital standards in effect at March 31, 2025 and December 31, 2024 ($ in thousands):

	Actual
	Regulatory Capital					Minimum			To Be Well
	Amount		Ratio			Requirement			Capitalized
At March 31, 2025:
Common Equity Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,746,998		11.63	%		7.00	%	n/a
Trustmark National Bank		1,838,631		12.24	%		7.00	%		6.50	%
Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,806,998		12.03	%		8.50	%	n/a
Trustmark National Bank		1,838,631		12.24	%		8.50	%		8.00	%
Total Capital (to Risk Weighted Assets)
Trustmark Corporation	$	2,118,632		14.10	%		10.50	%	n/a
Trustmark National Bank		2,026,479		13.49	%		10.50	%		10.00	%
Tier 1 Leverage (to Average Assets)
Trustmark Corporation	$	1,806,998		10.11	%		4.00	%	n/a
Trustmark National Bank		1,838,631		10.29	%		4.00	%		5.00	%
At December 31, 2024:
Common Equity Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,729,672		11.54	%		7.00	%	n/a
Trustmark National Bank		1,828,044		12.20	%		7.00	%		6.50	%
Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,789,672		11.94	%		8.50	%	n/a
Trustmark National Bank		1,828,044		12.20	%		8.50	%		8.00	%
Total Capital (to Risk Weighted Assets)
Trustmark Corporation	$	2,094,874		13.97	%		10.50	%	n/a
Trustmark National Bank		2,009,544		13.41	%		10.50	%		10.00	%
Tier 1 Leverage (to Average Assets)
Trustmark Corporation	$	1,789,672		9.99	%		4.00	%	n/a
Trustmark National Bank		1,828,044		10.21	%		4.00	%		5.00	%

Net Change in Components of Accumulated Other Comprehensive Income (Loss) and the Related Tax Effects

The following table presents the net change in the components of accumulated other comprehensive income (loss) and the related tax effects allocated to each component for the periods presented ($ in thousands).

	Three Months Ended March 31, 2025									Three Months Ended March 31, 2024
	Before Tax Amount			Tax (Expense) Benefit			Net of Tax Amount			Before Tax Amount			Tax (Expense) Benefit			Net of Tax Amount
Securities available for sale and transferred    securities:
Net unrealized holding gains (losses) arising    during the period	$	32,599		$	(8,149	)	$	24,450		$	(2,552	)	$	638		$	(1,914	)
Change in net unrealized holding loss on    securities transferred to held to maturity		3,425			(856	)		2,569			3,661			(915	)		2,746
Total securities available for sale    and transferred securities		36,024			(9,005	)		27,019			1,109			(277	)		832
Pension and other postretirement benefit plans:
Reclassification adjustments for changes    realized in net income:
Net change in prior service costs		4			(1	)		3			28			(7	)		21
Recognized net loss due to lump sum    settlements		(50	)		12			(38	)		—			—			—
Change in net actuarial loss		71			(17	)		54			95			(24	)		71
Total pension and other postretirement    benefit plans		25			(6	)		19			123			(31	)		92
Cash flow hedge derivatives:
Change in accumulated gain (loss) on effective    cash flow hedge derivatives		7,879			(1,970	)		5,909			(15,960	)		3,990			(11,970	)
Reclassification adjustment for (gain) loss    realized in net income		2,680			(670	)		2,010			4,820			(1,205	)		3,615
Total cash flow hedge derivatives		10,559			(2,640	)		7,919			(11,140	)		2,785			(8,355	)
Total other comprehensive income (loss)	$	46,608		$	(11,651	)	$	34,957		$	(9,908	)	$	2,477		$	(7,431	)

Summary of Changes in Balances of Accumulated Other Comprehensive Income (Loss)

The following table presents the changes in the balances of each component of accumulated other comprehensive income (loss) for the periods presented ($ in thousands). All amounts are presented net of tax.

	Securities Available for Sale and Transferred Securities			Defined Benefit Pension Items			Cash Flow Hedge Derivatives			Total
Balance at January 1, 2025	$	(66,885	)	$	(4,721	)	$	(12,053	)	$	(83,659	)
Other comprehensive income (loss) before    reclassification		27,019			—			5,909			32,928
Amounts reclassified from accumulated other    comprehensive income (loss)		—			19			2,010			2,029
Net other comprehensive income (loss)		27,019			19			7,919			34,957
Balance at March 31, 2025	$	(39,866	)	$	(4,702	)	$	(4,134	)	$	(48,702	)
Balance at January 1, 2024	$	(204,670	)	$	(6,075	)	$	(8,978	)	$	(219,723	)
Other comprehensive income (loss) before    reclassification		832			—			(11,970	)		(11,138	)
Amounts reclassified from accumulated other    comprehensive income (loss)		—			92			3,615			3,707
Net other comprehensive income (loss)		832			92			(8,355	)		(7,431	)
Balance at March 31, 2024	$	(203,838	)	$	(5,983	)	$	(17,333	)	$	(227,154	)