
December 31, 2022	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-Sale
U.S. Treasury notes	$	675.1	$	2.1	$	(34.5)	$	642.7
State, county, and municipal securities	314.3		—		(50.6)		263.7
Obligations of U.S. government agencies	216.2		—		(17.3)		198.9
U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations	4,685.5		0.2		(426.0)		4,259.7
Private mortgage-backed securities	264.9		—		(36.9)		228.0
Collateralized loan obligations	1,145.2		—		(33.6)		1,111.6
Corporate Securities	272.3		—		(30.8)		241.5

Total	$	7,573.5	$	2.3	$	(629.7)	$	6,946.1


December 31, 2022	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Held-to Maturity
U.S. Treasury notes	$	396.6	$	—	$	396.6	$	—	$	(10.2)	$	386.4
State, county, and municipal securities	181.2		(0.1)		181.1		0.2		(31.6)		149.7
Obligations of U.S. government agencies	351.7		—		351.7		—		(49.6)		302.1
U.S agency residential & commercial mortgage-backed securities & collateralized mortgage obligations (1)	2,444.1		—		2,444.1		0.2		(301.6)		2,142.7

Corporate securities	80.1		(1.8)		78.3		—		(7.0)		71.3

Total	$	3,453.7	$	(1.9)	$	3,451.8	$	0.4	$	(400.0)	$	3,052.2
(1) Amortized cost presented above include $20.2 million of unamortized losses and $14.2 million of unamortized gains related to the 2021 and 2022 transfer of securities from available-for-sale to held-to-maturity.


December 31, 2021	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-Sale
U.S. Treasury notes	$	697.6	$	—	$	(12.9)	$	684.7
State, county, and municipal securities	434.7		2.1		(9.3)		427.5
Obligations of U.S. government agencies	356.0		0.1		(9.2)		346.9
U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations	2,027.3		14.1		(23.3)		2,018.1
Private mortgage-backed securities	174.4		0.1		(1.1)		173.4
Collateralized loan obligation	898.2		1.2		—		899.4
Corporate Securities	271.1		3.0		(3.6)		270.5

Total	$	4,859.3	$	20.6	$	(59.4)	$	4,820.5


December 31, 2021	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Held-to Maturity

State, county, and municipal securities	$	67.6	$	—	$	67.6	$	2.0	$	(0.4)	$	69.2

U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations	1,609.0		—		1,609.0		13.2		(35.3)		1,586.9

Corporate securities	11.0		—		11.0		0.4		—		11.4

Total	$	1,687.6	$	—	$	1,687.6	$	15.6	$	(35.7)	$	1,667.5
(1) Amortized cost presented above include $20.1 million of unamortized gains in U.S. agency residential and commercial mortgage-backed securities and collateralized mortgage obligations related to the 2021 transfer of securities from available-for-sale to held-to-maturity.

On February 1, 2022, in conjunction with the acquisition of GWB and under ASC 320, the Company transferred debt securities classified as held-to-maturity with an amortized cost of $10.7 million and an estimated fair value of $10.9 million to the available-for-sale category classification and transferred debt securities classified as available-for-sale with an amortized cost of $485.9 million and an estimated fair value of $463.6 million to the held-to-maturity classification to maintain the Company’s intended risk profile. The transfer of debt securities into the available-for-sale and held-to-maturity categories were recorded at fair value on the date of transfer. This discount, as well as the related unrealized loss in accumulated other comprehensive income (loss), will be amortized into interest income as a yield adjustment over the remaining term of the securities. The amortization of the unrealized loss reported in accumulated other comprehensive (loss) income will offset the effect on interest income of the accretion of the discount. No gains or losses were recorded at the time of transfer.

The following tables show the gross unrealized losses and fair values of investment securities, aggregated by investment category, and the length of time individual investment securities have been in a continuous unrealized loss position, as of December 31, 2022 and 2021.


	Less than 12 Months				12 Months or More				Total
December 31, 2022	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Available-for-Sale
U.S. Treasury notes	$	168.8	$	(4.7)	$	170.4	$	(29.8)	$	339.2	$	(34.5)
State, county, and municipal securities	104.9		(9.0)		146.1		(41.6)		251.0		(50.6)
Obligations of U.S. government agencies	152.2		(10.1)		46.1		(7.2)		198.3		(17.3)
U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations	3,299.7		(262.3)		948.4		(163.7)		4,248.1		(426.0)
Private mortgage-backed securities	133.1		(19.1)		94.9		(17.8)		228.0		(36.9)
Collateralized loan obligations	1,082.6		(33.1)		28.9		(0.5)		1,111.5		(33.6)
Corporate securities	130.6		(8.3)		110.8		(22.5)		241.4		(30.8)

Total	$	5,071.9	$	(346.6)	$	1,545.6	$	(283.1)	$	6,617.5	$	(629.7)


	Less than 12 Months				12 Months or More				Total
December 31, 2022	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Held-to-Maturity
U.S. Treasury notes	$	386.4	$	(10.2)	$	—	$	—	$	386.4	$	(10.2)
State, county and municipal securities	33.8		(4.0)		96.7		(27.6)		130.5		(31.6)
Obligations of U.S. government agencies	86.1		(9.9)		216.0		(39.7)		302.1		(49.6)
U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations	1,349.4		(156.1)		762.5		(145.5)		2,111.9		(301.6)
Corporate securities	68.2		(7.0)		—		—		68.2		(7.0)
Total	$	1,923.9	$	(187.2)	$	1,075.2	$	(212.8)	$	2,999.1	$	(400.0)


	Less than 12 Months				12 Months or More				Total
December 31, 2021	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Available-for-Sale
U.S. Treasury notes	$	684.7	$	(12.9)	$	—	$	—	$	684.7	$	(12.9)
State, county, and municipal securities	278.7		(9.1)		5.0		(0.2)		283.7		(9.3)
Obligations of U.S. government agencies	297.0		(8.9)		16.4		(0.3)		313.4		(9.2)
U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations	1,262.8		(23.0)		26.4		(0.3)		1,289.2		(23.3)
Private mortgage-backed securities	127.2		(1.1)		—		—		127.2		(1.1)
Corporate securities	109.9		(3.3)		20.9		(0.3)		130.8		(3.6)

Total	$	2,760.3	$	(58.3)	$	68.7	$	(1.1)	$	2,829.0	$	(59.4)


	Less than 12 Months				12 Months or More				Total
December 31, 2021	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Held-to-Maturity

State, county and municipal securities	$	29.0	$	(0.4)	$	—	$	—	$	29.0	$	(0.4)

U.S. agency residential mortgage-backed securities & collateralized mortgage obligations	1,038.7		(35.3)		—		—		1,038.7		(35.3)

Total	$	1,067.7	$	(35.7)	$	—	$	—	$	1,067.7	$	(35.7)

The Company acquired $2,699.0 million of investment securities in connection with the acquisition of GWB. Such securities were evaluated and it was determined that there were no investment securities that met the definition of a PCD asset and none were classified as PCD upon acquisition.

The Company determines credit losses on both available-for-sale and held-to-maturity investment securities by a discounted cash flow approach using the security’s effective interest rate at the time of purchase or upon acquisition. The allowance for credit losses is measured as the amount by which an investment security’s amortized cost exceeds the net present value of expected future cash flows. However, the amount of credit losses for available-for-sale investment securities is limited to the amount of a security’s unrealized loss. Credit losses on held-to-maturity investment securities are representative of current expected credit losses that may be incurred over the life of the investment. The allowance for credit losses is established through a charge to provision for credit losses in current period earnings.

The available-for-sale securities portfolio contains securities that are guaranteed by a sovereign entity or are generally considered to have non-credit related risks, such as interest rate risk or prepayment and liquidity factors. The Company considers whether the securities are issued by the federal government or its agencies and whether downgrades by bond rating agencies have occurred. The Company had no allowance for credit losses for available-for-sale investment securities as of December 31, 2022 and 2021.

As of December 31, 2022 and 2021, the Company had 1,222 and 285 individual investment securities, respectively, that were in an unrealized loss position, which was related primarily to fluctuations in current interest rates. As of December 31, 2022, the Company had the intent and ability to hold these investment securities for a period of time sufficient to allow for an anticipated recovery.

On a quarterly basis, the Company refreshes the credit quality of each held-to-maturity security. The following table summarizes the credit quality indicators of held-to-maturity securities at amortized cost for the periods indicated:


December 31, 2022	AAA		AA		A		BBB		BB		Not Rated		Total
U.S. Treasury notes	$	396.6	$	—	$	—	$	—	$	—	$	—	$	396.6
State, county, and municipal securities	68.3		92.8		11.5		—		—		8.6		181.2
Obligations of U.S. government agencies	351.7		—		—		—		—		—		351.7
U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations
FNMA/FHLMC	2,233.6		—		—		—		—		—		2,233.6
GNMA	210.5		—		—		—		—		—		210.5
Corporate securities	—		—		—		65.1		10.0		5.0		80.1

Total	$	3,260.7	$	92.8	$	11.5	$	65.1	$	10.0	$	13.6	$	3,453.7


December 31, 2021	AAA		AA		A		BBB		Not Rated		Total

State, county, and municipal securities	$	17.2	$	31.6	$	14.7	$	—	$	4.1	$	67.6

U.S. agency residential & commercial mortgage-backed securities & collateralized mortgage obligations
FNMA/FHLMC	1,439.1		—		—		—		—		1,439.1
GNMA	169.9		—		—		—		—		169.9
Corporate securities	—		—		4.0		7.0		—		11.0

Total	$	1,626.2	$	31.6	$	18.7	$	7.0	$	4.1	$	1,687.6

As of December 31, 2022 and 2021, the Company had $38.9 million and $16.6 million, respectively, of accrued interest receivable on the consolidated balance sheet. The Company does not consider accrued interest receivable in the carrying amount of financial assets held at the amortized cost basis or in the allowance for credit losses calculation.

For the year ended December 31, 2022, there were $0.3 million in gross realized gains and $46.8 million in gross realized losses, primarily related to the sale of $500.0 million US treasury notes. The gross realized losses were offset by $22.1 million in deferred gains realized related to the termination of the fair value derivative of $46.3 million for a net realized loss on the termination of $24.2 million. For the year ended December 31, 2021, there were $3.2 million gross realized gains and $2.1 million gross realized losses. There were no material gross realized gains and no material gross realized losses for the year ended December 31, 2020.

Maturities of securities do not reflect rate repricing opportunities present in adjustable-rate mortgage-backed securities. Maturities of mortgage-backed securities have been adjusted to reflect shorter maturities based upon estimated prepayments of principal. All other investment securities maturities are shown at contractual maturity dates.


	Available-for-Sale				Held-to-Maturity
December 31, 2022	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Within one year	$	48.8	$	48.1	$	2.5	$	2.5
After one year but within five years	1,478.9		1,419.8		607.6		581.6
After five years but within ten years	1,750.0		1,564.3		732.7		639.5
After ten years	4,295.8		3,913.9		2,110.9		1,828.6
Total	$	7,573.5	$	6,946.1	$	3,453.7	$	3,052.2

As of December 31, 2022, the Company held investment securities callable within one year with amortized costs and estimated fair values of $1,443.3 million and $1,356.5 million, respectively. These investment securities are primarily classified as available-for-sale and included in the “after ten years category” in the table above. As of December 31, 2022, the Company had no callable structured notes.

As of December 31, 2022 and 2021, the Company recorded amortized costs of $4,998.9 million and $2,617.8 million, respectively, for investment securities pledged to secure public deposits and securities sold under repurchase agreements and had approximate fair values as of December 31, 2022 and 2021 of $4,432.0 million and $2,610.8 million, respectively. All securities sold under repurchase agreements are with clients and mature on the next banking day. The Company retains possession of the underlying securities sold under repurchase agreements.

As of December 31, 2022 and 2021, the Company held $198.6 million and $53.8 million, respectively, in equity securities in a combination of FRB and FHLB stocks, which are restricted nonmarketable securities acquired to meet regulatory requirements. These securities are carried at cost.