v3.25.2
Investment Securities
6 Months Ended
Jun. 30, 2025
Investments, Debt and Equity Securities [Abstract]  
Investment Securities
The amortized cost and the approximate fair values of investment securities are summarized as follows:
June 30, 2025Amortized
Cost
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Estimated
Fair
Value
Available-for-Sale:
U.S. Treasury notes$245.7 $— $(11.8)$233.9 
State, county, and municipal securities249.2 — (35.8)213.4 
Obligations of U.S. government agencies213.2 — (6.5)206.7 
U.S. agency commercial mortgage-backed securities995.7 1.0 (49.6)947.1 
U.S. agency residential mortgage-backed securities1,198.2 1.2 (88.0)1,111.4 
U.S. agency collateralized mortgage obligations1,072.2 1.4 (80.0)993.6 
Private mortgage-backed securities205.5 — (23.2)182.3 
Collateralized loan obligation625.8 1.0 — 626.8 
Corporate securities239.0 — (12.0)227.0 
Total$5,044.5 $4.6 $(306.9)$4,742.2 

June 30, 2025
Amortized
Cost(1)
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Estimated
Fair
Value
Held-to-Maturity:
U.S. Treasury notes$100.0 $— $(0.1)$99.9 
State, county, and municipal securities175.8 0.2 (23.5)152.5 
Obligations of U.S. government agencies466.8 — (45.2)421.6 
U.S. agency commercial mortgage-backed securities369.7 — (24.8)344.9 
U.S. agency residential mortgage-backed securities1,013.4 0.2 (105.1)908.5 
U.S. agency collateralized mortgage obligations405.0 0.5 (54.1)351.4 
Corporate securities40.0 — (1.8)38.2 
Total$2,570.7 $0.9 $(254.6)$2,317.0 
(1) Amortized cost presented above is net of an allowance for credit losses of $0.7 million and includes $6.9 million of unamortized gains and $14.8 million of unamortized losses related to the 2021 and 2022 transfer of securities from available-for-sale to held-to-maturity, respectively.
December 31, 2024Amortized
Cost
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Estimated
Fair
Value
Available-for-Sale:
U.S. Treasury notes$245.0 $— $(18.1)$226.9 
State, county, and municipal securities252.0 — (40.0)212.0 
Obligations of U.S. government agencies224.1 — (10.8)213.3 
U.S. agency commercial mortgage-backed securities1,057.2 0.1 (74.5)982.8 
U.S. agency residential mortgage-backed securities1,301.2 0.4 (125.8)1,175.8 
U.S. agency collateralized mortgage obligations1,156.9 0.6 (106.6)1,050.9 
Private mortgage-backed securities218.1 — (27.6)190.5 
Collateralized loan obligation770.7 1.3 — 772.0 
Corporate securities249.6 — (16.7)232.9 
Total$5,474.8 $2.4 $(420.1)$5,057.1 
December 31, 2024
Amortized
Cost(1)
Gross
Unrealized
Gains
Gross
Unrealized
Losses
Estimated
Fair
Value
Held-to-Maturity:
U.S. Treasury notes$99.8 $— $(0.4)$99.4 
State, county, and municipal securities176.3 0.2 (26.7)149.8 
Obligations of U.S. government agencies470.1 — (59.9)410.2 
U.S. agency commercial mortgage-backed securities374.9 — (33.4)341.5 
U.S. agency residential mortgage-backed securities1,082.5 — (140.7)941.8 
U.S. agency collateralized mortgage obligations427.8 — (66.1)361.7 
Corporate securities57.0 — (2.8)54.2 
Total$2,688.4 $0.2 $(330.0)$2,358.6 
(1) Amortized cost presented above is net of an allowance for credit losses of $0.9 million and includes $8.0 million of unamortized gains and $15.9 million of unamortized losses related to the 2021 and 2022 transfer of securities from available-for-sale to held-to-maturity, respectively.
The following tables show the gross unrealized losses and fair values of available-for-sale investment securities and the length of time individual investment securities have been in an unrealized loss position as of June 30, 2025 and December 31, 2024.
 Less than 12 Months12 Months or MoreTotal
June 30, 2025Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Available-for-Sale:      
U.S. Treasury notes$— $— $233.9 $(11.8)$233.9 $(11.8)
State, county, and municipal securities— — 211.6 (35.8)211.6 (35.8)
Obligations of U.S. government agencies1.0 — 200.7 (6.5)201.7 (6.5)
U.S. agency commercial mortgage-backed securities— — 898.0 (49.6)898.0 (49.6)
U.S. agency residential mortgage-backed securities32.9 (0.6)1,022.3 (87.4)1,055.2 (88.0)
U.S. agency collateralized mortgage obligations6.8 — 936.5 (80.0)943.3 (80.0)
Private mortgage-backed securities— — 182.2 (23.2)182.2 (23.2)
Corporate securities13.0 — 192.1 (12.0)205.1 (12.0)
Total$53.7 $(0.6)$3,877.3 $(306.3)$3,931.0 $(306.9)
 Less than 12 Months12 Months or MoreTotal
December 31, 2024Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Available-for-Sale:      
U.S. Treasury notes$— $— $226.8 $(18.1)$226.8 $(18.1)
State, county, and municipal securities— — 210.1 (40.0)210.1 (40.0)
Obligations of U.S. government agencies3.6 — 206.2 (10.8)209.8 (10.8)
U.S. agency commercial mortgage-backed securities38.1 (0.4)934.9 (74.1)973.0 (74.5)
U.S. agency residential mortgage-backed securities33.7 (1.5)1,086.2 (124.3)1,119.9 (125.8)
U.S. agency collateralized mortgage obligations20.5 (0.3)987.1 (106.3)1,007.6 (106.6)
Private mortgage-backed securities— — 190.4 (27.6)190.4 (27.6)
Collateralized loan obligation10.0 — — — 10.0 — 
Corporate securities27.5 (0.5)205.5 (16.2)233.0 (16.7)
Total$133.4 $(2.7)$4,047.2 $(417.4)$4,180.6 $(420.1)
The Company determines the allowance for credit losses on both available-for-sale and held-to-maturity investment securities by a discounted cash flow approach when needed, using each security’s effective interest rate at the time of purchase or upon acquisition. The allowance for credit losses for available-for-sale investment securities 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 is limited to the amount of a security’s unrealized loss. The allowance for credit loss on held-to-maturity investment securities is representative of current expected credit losses that management expects to be incurred over the life of the investment and established through a charge to provision for credit losses in current period earnings. For held-to-maturity investment securities, the Company has the intent and ability to hold these investment securities to maturity.
The investment securities portfolio primarily 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 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.
As of June 30, 2025 and December 31, 2024, the Company had 641 and 670 individual available-for-sale investment securities, respectively, that were in an unrealized loss position, which was related primarily to fluctuations in current interest rates. As of June 30, 2025, the Company does not intend to sell nor is it more likely than not the Company will be required to sell any available-for-sale securities with unrealized losses.
The Company had no allowance for credit losses on available-for-sale investment securities as of June 30, 2025 and December 31, 2024.
On a quarterly basis, the Company refreshes the credit quality indicator of each held-to-maturity security. As of June 30, 2025 and December 31, 2024, the held-to-maturity portfolio is primarily composed of investment grade or better securities. The Company had a $0.7 million and a $0.9 million allowance for credit losses for held-to-maturity corporate and state, county, and municipal investment securities as of June 30, 2025 and December 31, 2024, respectively.
As of June 30, 2025 and December 31, 2024, the Company had $26.5 million and $29.6 million, respectively, of accrued interest receivable from investment securities on the consolidated balance sheets. Accrued interest receivable is presented as a separate line item on the consolidated balance sheets and is not included in the carrying value of our securities.
During the three months ended June 30, 2025 and 2024, there were no gross realized gains or losses on the disposition of available-for-sale investment securities.
The following schedule represents the amortized cost of debt securities by contractual maturity except for maturities of mortgage-backed securities, which have been adjusted to reflect shorter maturities based upon estimated prepayments of principal.
 Available-for-SaleHeld-to-Maturity
June 30, 2025Amortized
Cost
Estimated
Fair Value
Amortized
Cost
Estimated
Fair Value
Within one year$103.7 $102.4 $108.1 $108.0 
After one year but within five years1,296.0 1,244.0 446.6 427.8 
After five years but within ten years1,318.2 1,247.7 442.0 397.8 
After ten years2,326.6 2,148.1 1,574.0 1,383.4 
Total$5,044.5 $4,742.2 $2,570.7 $2,317.0 
As of June 30, 2025, the Company held investment securities callable within one year having amortized costs and estimated fair values of $1,064.8 million and $1,031.2 million, respectively. These investment securities are primarily included in the “after five year” categories in the table above.
As of June 30, 2025 and December 31, 2024, the Company had securities with carrying values of $3,315.7 million and $3,460.2 million, respectively, for investment securities pledged to secure public deposits, derivatives, and securities sold under repurchase agreements that had estimated fair values as of June 30, 2025 and December 31, 2024, of $3,049.9 million and $3,092.6 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 June 30, 2025 and December 31, 2024, the Company held $118.1 million and $177.4 million, respectively, in equity securities primarily in a combination of Federal Reserve Bank and Federal Home Loan Bank (“FHLB”) stocks, which are restricted nonmarketable securities acquired to meet regulatory requirements and related to outstanding borrowings. These securities are carried at cost.