Consistent with our business strategy, we intend to continue to increase the purchase and origination of automobile, recreational vehicle and manufactured home loans. During the three months ended March 31, 2021, we purchased $3.4 million of automobile loans, $3.0 million of recreational vehicle loans and $4.6 million of manufactured home loans. We intended to begin purchasing one- to four-family residential real estate loans during the first quarter of 2021; however, we have not finalized the process for loan submission but expect to begin purchasing these types of loans in the second quarter of 2021.
Investment Securities. Securities available-for-sale increased $14.8 million, or 82.8%, to $32.8 million at March 31, 2021 from $17.9 million at December 31, 2020. The increase in securities available-for-sale resulted from the purchase of $15.7 million of bonds, partially offset by bond maturities of $851,000.
Equity investment securities, which are mostly comprised of equity securities held in a directors’ retirement plan rabbi trust, decreased $352,000, or 53.3%, to $309,000 at March 31, 2021 from $661,000 at December 31, 2020 primarily as a result of a portion of the directors’ retirement plan being invested in the Company’s stock.
Premises and Equipment. Premises and equipment decreased $103,000, or 0.6%, to $16.6 million at March 31, 2021 from $16.7 million at December 31, 2020. The decrease resulted primarily from recognition of depreciation expense of $259,000, offset partially by purchases of $156,000.
Pension Plan Assets. Pension plan assets increased $609,000, or 7.0%, to $9.3 million at March 31, 2021 from $8.7 million at December 31, 2020. The increase resulted from estimated returns on pension assets of $486,000 and employer contributions of $382,000, offset by estimated benefits paid of $122,000 and interest costs of $137,000.
Deposits. Deposits increased $1.4 million, or 0.5%, to $310.9 million at March 31, 2021 from $309.5 million at December 31, 2020. Noninterest-bearing deposits decreased $8.8 million, or 13.4%, to $56.9 million at March 31, 2021 from $65.7 million as of December 31, 2020. Interest-bearing accounts increased $10.2 million, or 4.2%, to $254.1 million at March 31, 2021 from $243.9 million at December 31, 2020. Interest-bearing checking accounts increased $3.2 million, or 10.0%, to $34.9 million at March 31, 2021 from $31.7 million at December 31, 2020. The largest increase in interest-bearing deposits was in savings accounts which increased $5.4 million, or 5.3%. Additionally, money market accounts increased $2.5 million, or 9.6%, to $28.8 million at March 31, 2021 from $26.3 million at December 31, 2020 and certificates of deposit decreased $918,000, or 1.1%, to $82.6 million at March 31, 2021 from $83.5 million at December 31, 2020.
Municipal deposits held at Generations Commercial Bank decreased $94,000, or 1.3%, to $7.0 million at March 31, 2021 from $7.1 million at December 31, 2020.
Federal Home Loan Bank Advances. Federal Home Loan Bank advances decreased $2.3 million, or 8.4%, to $25.3 million at March 31, 2021 from $27.6 million at December 31, 2020. The average cost of outstanding advances from the Federal Home Loan Bank was 2.01% at March 31, 2021, compared to our weighted average rate on deposits of 0.53% at that date.
Subordinated Debt and Other Borrowings. Subordinated debt and other borrowings were repaid in full during January 2021.
Total Equity. Total. equity increased $12.1 million, or 40.4%, to $41.9 million at March 31, 2021 from $29.9 million at December 31, 2020. The increase resulted primarily from net proceeds of $13.1 million from the stock offering completed in January 2021 and net income of $353,000 million during the period, offset in part, by recording the $337,000 fair value of our shares of common stock held in directors’ retirement plans.