construction and multi-family real estate loans at a higher point in the market interest rate cycle. Our strategy is to continue to grow our loan portfolio, with a focus on commercial real estate, multi-family residential real estate and construction loans, while continuing to originate single-family residential real estate loans to support local homebuyers. The recent increase in one- to four-family residential real estate loans was due to our establishing new broker relationships and our recent efforts to balance our concentration of commercial real estate loans, particularly with respect to our level of regulatory capital.
Deposits. Deposits increased $25.6 million, or 4.0%, to $661.0 million at December 31, 2024 from $635.4 million at June 30, 2024. The increase was due primarily to an increase in certificates of deposit, which increased $25.3 million, or 9.7%, to $287.5 million at December 31, 2024 from $262.2 million at June 30, 2024, as customers continued to hold deposit products with higher interest rates. This increase was comprised of an increase of $30.7 million, or 30.2%, in certificates of deposit of $250,000 or greater (the limit for federal deposit insurance), and a decrease of $5.4 million, or 3.4%, in certificates of deposit in amounts of less than $250,000. As described above, all of our deposits are fully insured under the DIF. The increase in deposits was also due to a $17.1 million, or 20.0%, increase in money market accounts, to $102.5 million at December 31, 2024 from $85.5 million at June 30, 2024. The increases in certificates of deposit and money market accounts were offset partially by a decrease of $16.1 million, or 6.9%, in lower-costing NOW and savings accounts from a total of $235.3 million at June 30, 2024 to $219.2 million at December 31, 2024.
Borrowings. Borrowings, which consisted solely of Federal Home Loan Bank of Boston advances, increased $16.0 million, or 12.4%, to $145.5 million at December 31, 2024, compared to $129.5 million from June 30, 2024. Advances were used to fund loan growth that exceeded our increase in deposits, described above.
Total Surplus. Total surplus increased $37,000 and was $80.3 million at each of December 31, 2024 and June 30, 2024. Total surplus increased due to a $296,000 decrease in accumulated other comprehensive loss to $1.5 million at December 31, 2024, partially offset by net loss of $259,000 for the six months ended December 31, 2024.
Comparison of Operating Results for the Three Months Ended December 31, 2024 and 2023
General. We recorded net income of $373,000 and $272,000 for the three months ended December 31, 2024 and 2023, respectively. The increase in net income was due to an increase in interest and dividend income and a decrease in operating expense, partially offset by increases in interest expense and the provision for credit losses, and a decrease in other income.
Interest and Dividend Income. Interest and dividend income increased $2.0 million, or 23.7%, to $10.5 million for the three months ended December 31, 2024, from $8.5 million for the three months ended December 31, 2023. Interest and fees on loans, which is our primary source of interest income, increased $1.7 million, or 22.2%, to $9.2 million for the three months ended December 31, 2024, from $7.6 million for the three months ended December 31, 2023.
The average balance of loans increased by $74.3 million, or 11.6%, to $716.3 million for the three months ended December 31, 2024, over the average balance for the three months ended December 31, 2023, while the average yield on loans increased by 45 basis points to 5.16% for the three months ended December 31, 2024, from 4.71% for the three months ended December 31, 2023. The increase in the average yield was due to increases in market interest rates as well as in improvement in the composition of our loan portfolio to include a higher percentage of higher yielding construction and commercial real estate loans, as well as multi-family residential real estate loans. The increase in average balance was due to our continuing to pursue new commercial relationships.
Interest Expense. Total interest expense increased $1.6 million, or 31.5%, to $6.5 million for the three months ended December 31, 2024, compared to $4.9 million for the three months ended December 31, 2023. Interest expense on deposits increased $1.1 million, or 29.1%, to $4.9 million for the three months ended December 31, 2024, from $3.8 million for the three months ended December 31, 2023. Our average balance of interest-bearing deposits increased $63.7 million, or 11.9%, to $601.2 million, while our average cost of deposits increased 44 basis points to 3.29% for the three months ended December 31, 2024, from 2.85% for the three months ended December 31, 2023. The increase in the average cost of deposits was due to increases in market interest rates as well as a higher percentage of our deposits consisting of certificates of deposit, which bear higher rates than other deposit categories.
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