NONINTEREST EXPENSE
Noninterest expense increased $2.8 million to $108.5 million for the third quarter of 2023 from $105.7 million in the prior quarter, primarily driven by a $10.0 million increase in other expenses, which includes $8.7 million in expenses associated with strategic cost saving initiatives and $2.0 million in merger-related costs. Adjusted operating noninterest expense,(1) which excludes amortization of intangible assets ($2.2 million in both the third quarter and second quarter of 2023), expenses associated with strategic cost savings initiatives ($8.7 million in the third quarter and $3.9 million in the second quarter of 2023), and merger-related costs associated with the American National merger ($2.0 million in the third quarter of 2023), decreased $3.9 million to $95.7 million for the third quarter of 2023 from $99.5 million in the prior quarter. The decrease in adjusted operating noninterest expense(1) was primarily due to a $1.6 million decrease in salaries and benefits expense reflecting the impact of strategic cost saving initiatives, a $1.1 million decrease in professional services expense related to strategic projects in the prior quarter, a $643,000 decrease in technology and data processing expense, and a $598,000 decrease in marketing and advertising expense.
INCOME TAXES
The effective tax rate for the three months ended September 30, 2023 and 2022 was 17.6% and 17.0%, respectively, and the effective tax rate for the nine months ended September 30, 2023 and 2022 was 16.3% and 17.0%, respectively.
BALANCE SHEET
At September 30, 2023, total assets were $20.7 billion, an increase of $133.9 million or approximately 2.6% (annualized) from June 30, 2023, and an increase of $786.0 million or approximately 3.9% from September 30, 2022. Total assets increased from the prior quarter primarily due to a $216.7 million increase in LHFI (net of deferred fees and costs), partially offset by a $110.3 million decrease in investment securities due primarily to the decline in market value of the AFS securities portfolio due to the impact of market interest rates. Total assets increased from the prior year period primarily due to a $1.4 billion increase in LHFI (net of deferred fees and costs), partially offset by a $607.7 million decrease in investment securities due primarily to the sale of AFS securities in the first and third quarters of 2023.
At September 30, 2023, LHFI (net of deferred fees and costs) totaled $15.3 billion, an increase of $216.7 million or 5.7% (annualized) from $15.1 billion at June 30, 2023. Average LHFI (net of deferred fees and costs) totaled $15.1 billion at September 30, 2023, an increase of $393.5 million or 10.6% (annualized) from the prior quarter. At September 30, 2023, both LHFI (net of deferred fees and costs) and average LHFI (net of deferred fees and costs) increased $1.4 billion from September 30, 2022. LHFI (net of deferred fees and costs) increased from the prior quarter primarily due to increases in the multifamily real estate and other commercial portfolios and increased from the same period in the prior year primarily due to increases in the commercial and industrial and commercial real estate non-owner occupied portfolios.
At September 30, 2023, total investments were $3.0 billion, a decrease of $110.3 million from June 30, 2023 and a decrease of $607.7 million from September 30, 2022. AFS securities totaled $2.1 billion at September 30, 2023, $2.2 billion at June 30, 2023, and $2.7 billion at September 30, 2022. At September 30, 2023, total net unrealized losses on the AFS securities portfolio were $523.1 million, compared to $450.1 million at June 30, 2023 and $507.7 million at September 30, 2022. Held to maturity (“HTM”) securities are carried at cost and totaled $843.3 million at September 30, 2023, $849.6 million at June 30, 2023, and $841.3 million at September 30, 2022 and had net unrealized losses of $81.2 million at September 30, 2023, compared to $41.8 million at June 30, 2023 and $75.9 million at September 30, 2022.
At September 30, 2023, total deposits were $16.8 billion, an increase of $374.5 million or approximately 9.1% (annualized) from June 30, 2023. Average deposits at September 30, 2023 increased from the prior quarter by $515.5 million or 12.6% (annualized). Total deposits at September 30, 2023 increased $240.3 million or 1.5% from September 30, 2022, and quarterly average deposits at September 30, 2023 increased $307.4 million or 1.9% from the same period in the prior year. Total deposits increased from the prior quarter and the prior year period primarily due to increases in interest bearing customer deposits and brokered deposits, partially offset by decreases in demand deposits.
At September 30, 2023, total borrowings were $1.0 billion, a decrease of $299.6 million from June 30, 2023, and an increase of $351.1 million from September 30, 2022. Total borrowings decreased from the prior quarter primarily due to