Securities

9 Months Ended

Sep. 30, 2025

Investments, Debt and Equity Securities [Abstract]

4. SECURITIES

The amortized cost and fair value of investment securities were as follows:


	September 30, 2025
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(Dollars in thousands)
Available for Sale
Corporate debt securities	$	7,935	$	1,725	$	—		$	9,660
Collateralized mortgage obligations		220,188		—		(2,999	)		217,189
Mortgage-backed securities		106,233		88		(801	)		105,520
Total	$	334,356	$	1,813	$	(3,800	)	$	332,369
Held to Maturity
U.S. Government agencies	$	5,989	$	4	$	(1	)	$	5,992
States and political subdivisions		70,375		390		(1,430	)		69,335
Corporate debt securities		12,000		—		(2,160	)		9,840
Collateralized mortgage obligations		231,085		835		(12,483	)		219,437
Mortgage-backed securities		9,580,644		8,479		(912,055	)		8,677,068
Total	$	9,900,093	$	9,708	$	(928,129	)	$	8,981,672


	December 31, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(Dollars in thousands)
Available for Sale
Corporate debt securities	$	14,350	$	2,035	$	(60	)	$	16,325
Collateralized mortgage obligations		216,142		81		(3,233	)		212,990
Mortgage-backed securities		108,524		41		(920	)		107,645
Total	$	339,016	$	2,157	$	(4,213	)	$	336,960
Held to Maturity
U.S. Government agencies	$	5,861	$	—	$	(44	)	$	5,817
States and political subdivisions		98,125		220		(2,510	)		95,835
Corporate debt securities		12,000		—		(3,840	)		8,160
Collateralized mortgage obligations		232,345		—		(24,128	)		208,217
Mortgage-backed securities		10,409,133		380		(1,345,063	)		9,064,450
Total	$	10,757,464	$	600	$	(1,375,585	)	$	9,382,479

The investment securities portfolio is measured for expected credit losses by segregating the portfolio into two general classifications and applying the appropriate expected credit losses methodology. Investment securities classified as available for sale or held to maturity are evaluated for expected credit losses under FASB ASC Topic 326, “Financial Instruments – Credit Losses” (“CECL”).

Available for sale securities. For available for sale securities in an unrealized loss position, the amount of the expected credit losses recognized in earnings depends on whether an entity intends to sell the security or more likely than not will be required to sell the security before recovery of its amortized cost basis less any current-period credit loss. If an entity intends to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis less any current-period credit loss, the expected credit losses will be recognized in earnings equal to the entire difference between the investment’s amortized cost basis and its fair value at the balance sheet date. If an entity does not intend to sell the security and it is not more likely than not that the entity will be required to sell the security before recovery of its amortized cost basis less any current-period loss, the expected credit losses will be separated into the amount representing the credit-related portion of the impairment loss (“credit loss”) and the noncredit portion of the impairment loss (“noncredit portion”). The amount of the total expected credit losses related to the credit loss is determined based on the difference between the present value of cash flows expected to be collected and the amortized cost basis and such difference is recognized in earnings. The amount of the total expected credit losses related to the noncredit portion is recognized in other comprehensive income, net of applicable taxes. The previous amortized cost basis less the expected credit losses recognized in earnings will become the new amortized cost basis of the investment.

As of September 30, 2025, management does not have the intent to sell any of the securities classified as available for sale before a recovery of cost. In addition, management believes it is more likely than not that the Company will not be required to sell any of its investment securities before a recovery of cost. The unrealized losses are largely due to changes in market interest rates and spread relationships since the time the underlying securities were purchased. The fair value is expected to recover as the securities approach their maturity date or repricing date, or if market yields for such investments decline. Management does not believe any of the securities are impaired due to reasons of credit quality. Accordingly, as of September 30, 2025, management believes that there is no potential for credit losses on available for sale securities.

Held to maturity securities. The Company’s held to maturity investments include mortgage-related bonds issued by either the Government National Mortgage Corporation (“Ginnie Mae”), Federal National Mortgage Association (“Fannie Mae”) or Federal Home Loan Mortgage Corporation (“Freddie Mac”). Ginnie Mae-issued securities are explicitly guaranteed by the U.S. government, while Fannie Mae- and Freddie Mac-issued securities are fully guaranteed by those respective United States government-sponsored agencies and conditionally guaranteed by the full faith and credit of the United States. The Company’s held to maturity securities also include taxable and tax-exempt municipal securities issued primarily by school districts, utility districts and municipalities located in Texas. The Company’s investment in municipal securities is exposed to credit risk. The securities are highly rated by major rating agencies and regularly reviewed by management. A significant portion are guaranteed or insured by either the Texas Permanent School Fund, Assured Guaranty or Build America Mutual. As of September 30, 2025, the Company’s municipal securities represent 0.7% of the securities portfolio. Management has the ability and intent to hold the securities classified as held to maturity until they mature, at which time the Company will receive full value for the securities. Accordingly, as of September 30, 2025, management believes that there is no potential for material credit losses on held to maturity securities.

Securities with unrealized losses, segregated by length of time, that have been in a continuous loss position were as follows:


	September 30, 2025
	Less than 12 Months					12 Months or More					Total
	Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses
	(Dollars in thousands)
Available for Sale
Collateralized mortgage obligations	$	65,479	$	(395	)	$	147,510	$	(2,604	)	$	212,989	$	(2,999	)
Mortgage-backed securities		9,421		(62	)		89,917		(739	)		99,338		(801	)
Total	$	74,900	$	(457	)	$	237,427	$	(3,343	)	$	312,327	$	(3,800	)
Held to Maturity
U.S. Government agencies	$	—	$	—		$	1,972	$	(1	)	$	1,972	$	(1	)
States and political subdivisions		—		—			23,522		(1,430	)		23,522		(1,430	)
Corporate debt securities		—		—			9,840		(2,160	)		9,840		(2,160	)
Collateralized mortgage obligations		566		(5	)		171,256		(12,478	)		171,822		(12,483	)
Mortgage-backed securities		4,778		(45	)		8,101,183		(912,010	)		8,105,961		(912,055	)
Total	$	5,344	$	(50	)	$	8,307,773	$	(928,079	)	$	8,313,117	$	(928,129	)


	December 31, 2024
	Less than 12 Months					12 Months or More					Total
	Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses
	(Dollars in thousands)
Available for Sale
Corporate debt securities	$	2,040	$	(60	)	$	—	$	—		$	2,040	$	(60	)
Collateralized mortgage obligations		47,114		(307	)		125,942		(2,926	)		173,056		(3,233	)
Mortgage-backed securities		6,837		(53	)		89,513		(867	)		96,350		(920	)
Total	$	55,991	$	(420	)	$	215,455	$	(3,793	)	$	271,446	$	(4,213	)
Held to Maturity
U.S. Government agencies	$	5,817	$	(44	)	$	—	$	—		$	5,817	$	(44	)
States and political subdivisions		23,270		(113	)		47,943		(2,397	)		71,213		(2,510	)
Corporate debt securities		—		—			8,160		(3,840	)		8,160		(3,840	)
Collateralized mortgage obligations		28,362		(663	)		179,855		(23,465	)		208,217		(24,128	)
Mortgage-backed securities		331,265		(4,647	)		8,646,541		(1,340,416	)		8,977,806		(1,345,063	)
Total	$	388,714	$	(5,467	)	$	8,882,499	$	(1,370,118	)	$	9,271,213	$	(1,375,585	)

At September 30, 2025, and December 31, 2024, there were 756 securities and 949 securities, respectively, in an unrealized loss position for 12 months or more.

The table below summarizes the amortized cost and fair value of investment securities at September 30, 2025, by contractual maturity. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations at any time with or without call or prepayment penalties.


	Held to Maturity				Available for Sale
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
	(Dollars in thousands)
Due in one year or less	$	16,568	$	16,593	$	—	$	—
Due after one year through five years		41,525		41,589		—		—
Due after five years through ten years		30,271		26,985		7,935		9,660
Due after ten years		—		—		—		—
Subtotal		88,364		85,167		7,935		9,660
Mortgage-backed securities and collateralized mortgage obligations		9,811,729		8,896,505		326,421		322,709
Total	$	9,900,093	$	8,981,672	$	334,356	$	332,369

At September 30, 2025, and December 31, 2024, the Company did not own securities of any one issuer (other than the U.S. government and its agencies) for which aggregate adjusted cost exceeded 10% of the consolidated shareholders’ equity at such respective dates.

Securities with an amortized cost of $7.51 billion and $10.26 billion and a fair value of $6.78 billion and $8.91 billion at September 30, 2025, and December 31, 2024, respectively, were pledged to collateralize public deposits and for other purposes required or permitted by law.

The Company recorded no gain or loss on the sale of investment securities for the three and nine months ended September 30, 2025. The Company recorded no gain or loss on the sale of investment securities for the three months ended September 30, 2024, and a $9.4 million net loss on the sale of investment securities for the nine months ended September 30, 2024. As of September 30, 2025, the Company did not own any non-agency collateralized mortgage obligations.

Visa Class B-1 Stock Exchange. During the second quarter of 2024, the Bank tendered all of its shares of Visa Class B-1 common stock in exchange for a combination of Visa Class B-2 common stock and Visa Class C common stock, pursuant to the terms and subject to the conditions of the public offering of Visa to exchange its Class B-1 common stock for a combination of shares of its Class B-2 common stock and Class C common stock, which expired on May 3, 2024. The Company recorded a gain of $20.6 million during the second quarter of 2024 based on the conversion privilege of the Class C common stock and the closing price of Visa Class

A common stock. In the exchange, the Bank received 48,492 shares of Class B-2 stock, recorded at zero cost basis, and 19,245 shares of Class C common stock and has subsequently sold all shares of Class C stock.