Shareholders' Equity (Tables)

9 Months Ended

Sep. 30, 2022

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 September 30, 2022 and December 31, 2021 ($ in thousands):

	Actual
	Regulatory Capital					Minimum			To Be Well
	Amount		Ratio			Requirement			Capitalized
At September 30, 2022:
Common Equity Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,461,134		10.63	%		7.00	%	n/a
Trustmark National Bank		1,548,097		11.26	%		7.00	%		6.50	%
Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,521,134		11.06	%		8.50	%	n/a
Trustmark National Bank		1,548,097		11.26	%		8.50	%		8.00	%
Total Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,766,527		12.85	%		10.50	%	n/a
Trustmark National Bank		1,670,283		12.15	%		10.50	%		10.00	%
Tier 1 Leverage (to Average Assets)
Trustmark Corporation	$	1,521,134		9.01	%		4.00	%	n/a
Trustmark National Bank		1,548,097		9.19	%		4.00	%		5.00	%
At December 31, 2021:
Common Equity Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,425,227		11.29	%		7.00	%	n/a
Trustmark National Bank		1,518,599		12.03	%		7.00	%		6.50	%
Tier 1 Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,485,227		11.77	%		8.50	%	n/a
Trustmark National Bank		1,518,599		12.03	%		8.50	%		8.00	%
Total Capital (to Risk Weighted Assets)
Trustmark Corporation	$	1,710,700		13.55	%		10.50	%	n/a
Trustmark National Bank		1,621,030		12.84	%		10.50	%		10.00	%
Tier 1 Leverage (to Average Assets)
Trustmark Corporation	$	1,485,227		8.73	%		4.00	%	n/a
Trustmark National Bank		1,518,599		8.94	%		4.00	%		5.00	%

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

The following tables present 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). The amortization of prior service cost, recognized net loss due to lump sum settlements and change in net actuarial loss are included in the computation of net periodic benefit cost (see Note 10 – Defined Benefit and Other Postretirement Benefits for additional details). Reclassification adjustments related to pension and other postretirement benefit plans are included in salaries and employee benefits and other expense in the accompanying consolidated statements of income. Reclassification adjustments related to the cash flow hedge derivative are included in interest and fees on LHFS and LHFI in the accompanying consolidated statements of income.

	Three Months Ended September 30, 2022									Three Months Ended September 30, 2021
	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	$	(114,317	)	$	28,580		$	(85,737	)	$	(12,543	)	$	3,136		$	(9,407	)
Change in net unrealized holding loss on    securities transferred to held to maturity		1,800			(450	)		1,350			636			(159	)		477
Total securities available for sale    and transferred securities		(112,517	)		28,130			(84,387	)		(11,907	)		2,977			(8,930	)
Pension and other postretirement benefit plans:
Reclassification adjustments for changes    realized in net income:
Net change in prior service costs		28			(7	)		21			28			(7	)		21
Recognized net loss due to lump sum    settlements		—			—			—			183			(46	)		137
Change in net actuarial loss		295			(74	)		221			444			(111	)		333
Total pension and other postretirement    benefit plans		323			(81	)		242			655			(164	)		491
Cash flow hedge derivatives:
Change in accumulated gain (loss) on effective    cash flow hedge derivatives		(19,524	)		4,881			(14,643	)		—			—			—
Reclassification adjustment for (gain) loss realized    in net income		(643	)		161			(482	)		—			—			—
Total cash flow hedge derivatives		(20,167	)		5,042			(15,125	)		—			—			—
Total other comprehensive income (loss)	$	(132,361	)	$	33,091		$	(99,270	)	$	(11,252	)	$	2,813		$	(8,439	)

	Nine Months Ended September 30, 2022									Nine Months Ended September 30, 2021
	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	$	(314,517	)	$	78,630		$	(235,887	)	$	(27,731	)	$	6,933		$	(20,798	)
Change in net unrealized holding loss on    securities transferred to held to maturity		(31,451	)		7,863			(23,588	)		2,083			(521	)		1,562
Total securities available for sale    and transferred securities		(345,968	)		86,493			(259,475	)		(25,648	)		6,412			(19,236	)
Pension and other postretirement benefit plans:
Reclassification adjustments for changes    realized in net income:
Net change in prior service costs		83			(21	)		62			84			(21	)		63
Recognized net loss due to lump sum    settlements		—			—			—			183			(46	)		137
Change in net actuarial loss		914			(228	)		686			1,342			(335	)		1,007
Total pension and other postretirement    benefit plans		997			(249	)		748			1,609			(402	)		1,207
Cash flow hedge derivatives:
Change in accumulated gain (loss) on effective    cash flow hedge derivatives		(19,524	)		4,881			(14,643	)		—			—			—
Reclassification adjustment for (gain) loss realized    in net income		(643	)		161			(482	)		—			—			—
Total cash flow hedge derivatives		(20,167	)		5,042			(15,125	)		—			—			—
Total other comprehensive income (loss)	$	(365,138	)	$	91,286		$	(273,852	)	$	(24,039	)	$	6,010		$	(18,029	)

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, 2022	$	(17,774	)	$	(14,786	)	$	—		$	(32,560	)
Other comprehensive income (loss) before reclassification		(259,475	)		—			(14,643	)		(274,118	)
Amounts reclassified from accumulated other    comprehensive income (loss)		—			748			(482	)		266
Net other comprehensive income (loss)		(259,475	)		748			(15,125	)		(273,852	)
Balance at September 30, 2022	$	(277,249	)	$	(14,038	)	$	(15,125	)	$	(306,412	)
Balance at January 1, 2021	$	17,331		$	(18,382	)	$	—		$	(1,051	)
Other comprehensive income (loss) before reclassification		(19,236	)		—			—			(19,236	)
Amounts reclassified from accumulated other    comprehensive income (loss)		—			1,207			—			1,207
Net other comprehensive income (loss)		(19,236	)		1,207			—			(18,029	)
Balance at September 30, 2021	$	(1,905	)	$	(17,175	)	$	—		$	(19,080	)