This table provides detailed information about securities available for sale at September 30, 2025 and December 31, 2024 (in thousands):


September 30, 2025	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	2,180,744	$	17,757	$	(750	)	$	2,197,751
U.S. Agencies		81,171		422		(167	)		81,426
Mortgage-backed		8,160,828		55,196		(373,749	)		7,842,275
State and political subdivisions		2,541,797		23,996		(86,291	)		2,479,502
Corporates		228,546		217		(6,227	)		222,536
Collateralized loan obligations		554,063		878		(151	)		554,790
Total	$	13,747,149	$	98,466	$	(467,335	)	$	13,378,280


December 31, 2024	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	1,331,394	$	2,751	$	(8,072	)	$	1,326,073
U.S. Agencies		129,246		126		(325	)		129,047
Mortgage-backed		4,945,548		339		(524,957	)		4,420,930
State and political subdivisions		1,309,126		487		(91,044	)		1,218,569
Corporates		330,739		60		(13,629	)		317,170
Collateralized loan obligations		361,623		1,060		(138	)		362,545
Total	$	8,407,676	$	4,823	$	(638,165	)	$	7,774,334

Securities may be disposed of before contractual maturities due to sales by the Company or because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

During 2025, related to the acquisition of HTLF, the Company acquired securities available for sale with an Acquisition Date fair value of $3.1 billion.

There were $11.6 billion and $10.5 billion of securities pledged to secure U.S. Government deposits, other public deposits, certain trust deposits, derivative transactions, and repurchase agreements at September 30, 2025 and December 31, 2024, respectively.

Accrued interest on securities available for sale totaled $74.8 million and $43.1 million as of September 30, 2025 and December 31, 2024, respectively, and is included in the Accrued income line on the Company’s Consolidated Balance Sheets. The total amount of accrued interest is excluded from the amortized cost of available-for-sale securities presented above. Further, the Company has elected not to measure an ACL for accrued interest receivable.

The following table shows the Company’s available-for-sale investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at September 30, 2025 and December 31, 2024 (in thousands):


	Less than 12 months							12 months or more							Total
September 30, 2025	Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses
Description of Securities
U.S. Treasury		7	$	79,522	$	(168	)		7	$	75,611	$	(582	)		14	$	155,133	$	(750	)
U.S. Agencies		1		8,583		(167	)		—		—		—			1		8,583		(167	)
Mortgage-backed		99		697,377		(3,896	)		829		2,951,837		(369,853	)		928		3,649,214		(373,749	)
State and political subdivisions		147		610,974		(17,306	)		1,215		800,722		(68,985	)		1,362		1,411,696		(86,291	)
Corporates		2		2,244		(6	)		161		194,933		(6,221	)		163		197,177		(6,227	)
Collateralized loan obligations		11		109,671		(102	)		3		15,847		(49	)		14		125,518		(151	)
Total		267	$	1,508,371	$	(21,645	)		2,215	$	4,038,950	$	(445,690	)		2,482	$	5,547,321	$	(467,335	)


	Less than 12 months							12 months or more							Total
December 31, 2024	Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses
Description of Securities
U.S. Treasury		93	$	635,739	$	(6,319	)		9	$	142,518	$	(1,753	)		102	$	778,257	$	(8,072	)
U.S. Agencies		4		20,858		(46	)		5		56,712		(279	)		9		77,570		(325	)
Mortgage-backed		159		1,293,953		(22,468	)		834		3,055,882		(502,489	)		993		4,349,835		(524,957	)
State and political subdivisions		264		173,006		(2,392	)		1,629		953,458		(88,652	)		1,893		1,126,464		(91,044	)
Corporates		—		—		—			239		315,109		(13,629	)		239		315,109		(13,629	)
Collateralized loan obligations		7		47,222		(88	)		5		30,521		(50	)		12		77,743		(138	)
Total		527	$	2,170,778	$	(31,313	)		2,721	$	4,554,200	$	(606,852	)		3,248	$	6,724,978	$	(638,165	)

The unrealized losses in the Company’s investments were caused by changes in interest rates, and not from a decline in credit of the underlying issuers. The U.S. Treasury, U.S. Agency, and GSE mortgage-backed securities are all considered to be agency-backed securities with no risk of loss as they are either explicitly or implicitly guaranteed by the U.S. government. The changes in fair value in the agency-backed portfolios are solely driven by change in interest rates caused by changing economic conditions. The Company has no knowledge of any underlying credit issues and the cash flows underlying the debt securities have not changed and are not expected to be impacted by changes in interest rates.

For the State and political subdivision portfolio, the majority of the Company’s holdings are in general obligation bonds, which have a very low historical default rate due to issuers generally having unlimited taxing authority to service the debt. For the State and political, Corporates, and Collateralized loan obligations portfolios, the Company has a robust process for monitoring credit risk, including both pre-purchase and ongoing post-purchase credit reviews and analysis. The Company monitors credit ratings of all bond issuers in these segments and reviews available financial data, including market and sector trends.

As of September 30, 2025 and December 31, 2024, there was no ACL related to the Company’s available-for-sale securities as the decline in fair value did not result from credit issues.

The following table provides detailed information about securities held to maturity at September 30, 2025 and December 31, 2024, respectively (in thousands):


September 30, 2025	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Allowance for Credit Losses			Net Carrying Amount
U.S. Treasury	$	38,249	$	4	$	(115	)	$	38,138	$	—		$	38,249
U.S. Agencies		—		—		—			—		—			—
Mortgage-backed		2,573,708		170		(323,324	)		2,250,554		—			2,573,708
State and political subdivisions		3,042,275		13,072		(224,338	)		2,831,009		(1,845	)		3,040,430
Total	$	5,654,232	$	13,246	$	(547,777	)	$	5,119,701	$	(1,845	)	$	5,652,387


December 31, 2024	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Allowance for Credit Losses			Net Carrying Amount
U.S. Agencies	$	116,331	$	—	$	(581	)	$	115,750	$	—		$	116,331
Mortgage-backed		2,523,134		—		(418,482	)		2,104,652		—			2,523,134
State and political subdivisions		2,739,447		12,035		(222,946	)		2,528,536		(2,645	)		2,736,802
Total	$	5,378,912	$	12,035	$	(642,009	)	$	4,748,938	$	(2,645	)	$	5,376,267

Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

During 2025, related to the acquisition of HTLF, the Company acquired securities held to maturity with an Acquisition Date fair value of $438.9 million.

There were no sales of securities held to maturity during the three or nine months ended September 30, 2025 or 2024.

During the year ended December 31, 2022, securities with an amortized cost of $4.1 billion and a fair value of $3.8 billion were transferred from the available-for-sale classification to the held-to-maturity classification as the Company has the positive intent and ability to hold these securities to maturity. The transfers of securities were made at fair value at the time of transfer. The unrealized holding gain or loss at the time of transfer is retained in AOCI and will be amortized over the remaining life of the securities, offsetting the related amortization of discount or premium on the transferred securities. No gains or losses were recognized at the time of the transfers. The amortized cost balance of securities held to maturity in the tables above includes a net unamortized unrealized loss of $147.0 million and $171.3 million at September 30, 2025 and December 31, 2024, respectively.

Accrued interest on securities held to maturity totaled $21.3 million and $25.6 million as of September 30, 2025 and December 31, 2024, respectively, and is included in the Accrued income line on the Company’s Consolidated Balance Sheets. The total amount of accrued interest is excluded from the amortized cost of

held-to-maturity securities presented above. Further, the Company has elected not to measure an ACL for accrued interest receivable.

The following table shows the Company’s held-to-maturity investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at September 30, 2025 and December 31, 2024, respectively (in thousands):


	Less than 12 months							12 months or more							Total
September 30, 2025	Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses
U.S. Treasury		6	$	30,638	$	(115	)		—	$	—	$	—			6	$	30,638	$	(115	)
U.S. Agencies		—		—		—			—		—		—			—		—		—
Mortgage-backed		12		104,013		(1,198	)		262		2,037,057		(322,126	)		274		2,141,070		(323,324	)
State and political subdivisions		151		727,606		(48,914	)		1,353		1,468,551		(175,424	)		1,504		2,196,157		(224,338	)
Total		169	$	862,257	$	(50,227	)		1,615	$	3,505,608	$	(497,550	)		1,784	$	4,367,865	$	(547,777	)


	Less than 12 months							12 months or more							Total
December 31, 2024	Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses			Count		Fair Value		Unrealized Losses
U.S. Agencies		—	$	—	$	—			10	$	115,750	$	(581	)		10	$	115,750	$	(581	)
Mortgage-backed		6		3,527		(103	)		263		2,101,125		(418,379	)		269		2,104,652		(418,482	)
State and political subdivisions		47		52,468		(2,030	)		1,414		1,972,927		(220,916	)		1,461		2,025,395		(222,946	)
Total		53	$	55,995	$	(2,133	)		1,687	$	4,189,802	$	(639,876	)		1,740	$	4,245,797	$	(642,009	)

The unrealized losses in the Company’s held-to-maturity portfolio were caused by changes in the interest rate environment. The U.S. Treasury, U.S. Agency and GSE mortgage-backed securities are considered to be agency-backed securities with no risk of loss as they are either explicitly or implicitly guaranteed by the U.S. government. Therefore, the Company’s expected lifetime loss for these portfolios is zero and there is no ACL recorded for these portfolios. The Company has no knowledge of any underlying credit issues and the cash flows underlying the debt securities have not changed and are not expected to be impacted by changes in interest rates.

For the State and political subdivision portfolio, the Company’s holdings are in general obligation bonds as well as private placement bonds, which have very low historical default rates due to issuers generally having unlimited taxing authority to service the debt. The Company has a robust process for monitoring credit risk, including both pre-purchase and ongoing post-purchase credit reviews and analysis. The Company monitors credit ratings of all bond issuers in these segments and reviews available financial data, including market and sector trends. The underlying bonds are evaluated for credit losses in conjunction with management’s estimate of the ACL based on credit rating.

The following tables show the amortized cost basis by credit rating of the Company’s held-to-maturity State and political subdivisions bond investments at September 30, 2025 and December 31, 2024 (in thousands):


	Amortized Cost Basis by Credit Rating - HTM Debt Securities
September 30, 2025	AAA		AA		A		BBB		BB		B		CCC-C		Total
State and political subdivisions:
Competitive	$	48,372	$	51,835	$	401,250	$	797,970	$	41,021	$	23,551	$	14,721	$	1,378,720
Utilities		774,751		754,910		110,326		22,895		673		—		—		1,663,555
Total state and political subdivisions	$	823,123	$	806,745	$	511,576	$	820,865	$	41,694	$	23,551	$	14,721	$	3,042,275


	Amortized Cost Basis by Credit Rating - HTM Debt Securities
December 31, 2024	AAA		AA		A		BBB		BB		CCC-C		Total
State and political subdivisions:
Competitive	$	—	$	—	$	424,690	$	610,351	$	36,628	$	21,990	$	1,093,659
Utilities		759,798		761,706		99,127		24,509		648		—		1,645,788
Total state and political subdivisions	$	759,798	$	761,706	$	523,817	$	634,860	$	37,276	$	21,990	$	2,739,447

Competitive held-to-maturity securities include not-for-profit enterprises that provide public functions such as housing, higher education or healthcare, but do so in a competitive environment. It also includes project financings that can have relatively high enterprise risk, such as deals backed by revenues from sports or convention facilities or start-up transportation revenues.

Utilities are public enterprises providing essential services with a monopoly or near-monopoly over the service area. This includes environmental utilities (water, sewer, solid waste), power utilities (electric distribution and generation, gas), and transportation utilities (airports, parking, toll roads, mass transit, ports).

All held-to-maturity securities were current and not past due at September 30, 2025 and December 31, 2024.

There were net unrealized losses of $6 thousand and net unrealized gains of $44 thousand on trading securities at September 30, 2025 and 2024, respectively. Net unrealized gains and losses are included in trading and investment banking income on the Company’s Consolidated Statements of Income. Securities sold not yet purchased totaled $13.0 million and $7.1 million at September 30, 2025 and December 31, 2024, respectively, and are classified within the Other liabilities line of the Company’s Consolidated Balance Sheets.

Investment in FRB stock is based on the capital structure of the investing bank, and investment in FHLB stock is mainly tied to the level of borrowings from the FHLB. These holdings are carried at cost. Equity securities with readily determinable fair values are generally traded on an exchange and market prices are readily available. Equity securities without readily determinable fair values include equity investments which are held by a subsidiary qualified as a Small Business Investment Company, as well as investments in low-income housing partnerships within the areas the Company serves. Unrealized gains or losses on equity securities with and without readily determinable fair values are recognized in the Investment securities gains, net line of the Company’s Consolidated Statements of Income.

During 2025, related to the acquisition of HTLF, the Company acquired other securities with an acquired fair value of $105.3 million as of the Acquisition Date, including $2.0 million of FRB and FHLB stock and $103.2 million of equity securities without readily determinable fair values.

The table below presents the changes in equity securities without readily determinable fair values for the three and nine months ended September 30, 2025 and 2024 (in thousands):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2025			2024			2025			2024
Beginning balance	$	533,749		$	371,123		$	416,750		$	394,035
Acquisition of HTLF		(19,675	)		—			103,211			—
Purchases of securities		34,919			33,397			83,749			45,154
Observable upward price adjustments		3,462			2,552			13,895			15,740
Observable downward price adjustments		(653	)		(268	)		(9,228	)		(6,042	)
Sales of securities and other activity		(10,783	)		(7,032	)		(67,358	)		(49,115	)
Ending balance	$	541,019		$	399,772		$	541,019		$	399,772

The following table presents the components of Investment securities (losses) gains, net for the three and nine months ended September 30, 2025 and September 30, 2024 (in thousands):


	Three Months Ended September 30,					Nine Months Ended September 30,
	2025			2024		2025			2024
Investment securities (losses) gains, net
Available-for-sale debt securities:
Gains realized on sales	$	91		$	—	$	514		$	139
Equity securities with readily determinable fair values:
Fair value adjustments, net		(7,103	)		340		22,513			291
Equity securities without readily determinable fair values:
Fair value adjustments, net		2,919			738		(2,384	)		(2,277	)
Sales		—			1,545		8,167			11,974
Total investment securities (losses) gains, net	$	(4,093	)	$	2,623	$	28,810		$	10,127