Nine months ended September 30, 2023 and 2022
The year over year increase of 187 basis points on interest earning assets was driven by significant increases to benchmark interest rates as well as strong loan growth throughout the period, specifically within the leases, commercial real estate-investor, construction and multi-family portfolios. The increases in benchmark interest rates impacted yields on the securities portfolio through the inverse relationship between interest rates and market value coupled with maturities and strategic sales of lower yielding assets and timely purchase of higher yielding securities as we work to increase the weighted average yield in the portfolio. Average securities available-for-sale decreased $367.0 million for the nine months ended September 30, 2023, compared to the nine months ended September 30, 2022, due to paydowns, changes in market value, and strategic sales. Due to market interest rate increases year over year, securities available-for-sale interest income was $34.7 million for the nine months ended September 30, 2023, compared to $26.1 million for the like 2022 period, reflecting an increase in yield of 134 basis points. Average loans, including loans held for sale, increased $438.0 million in the nine months ended September 30, 2023, compared to the nine months ended September 30, 2022, primarily driven by the growth in leases, commercial real estate-investor, construction, and multi-family portfolios. Growth in the loan portfolio, as well as the rising interest rate environment, resulted in $181.5 million of loan interest income in the nine months ended September 30, 2023, compared to $121.3 million in the like 2022 period, reflecting an increase in yield of 152 basis points.
Average balances of interest-bearing deposit accounts have decreased steadily since September 30, 2022 through the nine months ended September 30, 2023, from $3.32 billion to $2.89 billion, with such decreases reflected in all categories. We have continued to control the cost of funds over the periods reflected, with the rate of overall interest-bearing deposits increasing by 35 basis points to 43 basis points from eight basis points as of September 30, 2022. A 61 basis point increase in the cost of money market funds as of September 30, 2023, compared to September 30, 2022, was due to select deposit account exception pricing and drove a significant portion of the overall increase. Interest expense paid on time deposits also contributed to the increased cost of deposits year over year, as the cost of average time deposits increased 89 basis points to 114 basis points for the nine months ended September 30, 2023, compared to 25 basis points for the nine months ended September 30, 2022, primarily due to CD rate specials we offered.
Borrowing costs increased in the nine months ended September 30, 2023 primarily due to the increase in short term borrowings from higher average FHLB advance growth of $342.5 million since the nine months ended September 30, 2022, based on daily liquidity needs. Subordinated and junior subordinated debt interest expense remained flat over the periods presented. Senior notes interest expense had the most significant interest expense increase, as this issuance referenced three-month LIBOR, and rising market interest rates resulted in a 557 basis point increase to 10.95%, from 5.38% for the nine months ended September 30, 2022. We redeemed these notes on June 30, 2023, which contributed to the significant basis point increase due to the $362,000 in deferred issuance costs that were recognized as interest expense due to the early redemption. In the first quarter of 2023, we paid off the remaining balance of $9.0 million on the original $20.0 million term note issued in 2020, recorded within notes payable and other borrowings.
Our net interest margin (GAAP) increased 135 basis points to 4.66% for the nine months ended September 30, 2023, compared to 3.31% for the nine months ended September 30, 2022. Our net interest margin (TE) increased 135 basis points to 4.68% for the nine months ended September 30, 2023, compared to 3.33% for the nine months ended September 30, 2022. The increase in the current period, compared to the prior year like period, is primarily due to an increase in market interest rates, and the related rate resets on loans and securities during the past year, as well as continuing loan growth relative to a more modest increase in the cost of interest-bearing liabilities.
We continue to observe competitive pressure to maintain reduced interest rates on loans retained at renewal. While our loan prices are targeted to achieve certain returns on equity, significant competition for commercial and industrial loans as well as commercial real estate loans has put pressure on loan yields, and our stringent underwriting standards limit our ability to make higher-yielding loans.
The following tables set forth certain information relating to our average consolidated balance sheets and reflect the yield on average earning assets and cost of average interest-bearing liabilities for the periods indicated. These yields reflect the related interest, on an annualized basis, divided by the average balance of assets or liabilities over the applicable period. Average balances are derived from daily balances. For purposes of discussion, net interest income and net interest income to total earning assets in the following tables have been adjusted to a non-GAAP TE basis using a marginal rate of 21% in 2023 and 2022 to compare returns more appropriately on tax-exempt loans and securities to other earning assets.