Total investments were $507.9 million at March 31, 2023, compared to $569.0 million at December 31, 2022. At March 31, 2023, the available-for-sale securities totaled $418.1 million and the held-to-maturity securities totaled $89.7 million and comprised 82.3% and 17.7% of the overall portfolio, respectively. The unrealized losses on the held-to-maturity portfolio totaled $12.6 million and $14.6 million at March 31, 2023 and December 31, 2022, respectively. During the three month period ended March 31, 2023, $65.6 million in U.S. Treasury, tax-exempt municipals and mortgage-backed securities were sold at a net gain of $81 thousand. The proceeds were used to pay-down higher cost short-term borrowings.
Total deposits increased $189.4 million during the three months ending March 31, 2023. Noninterest-bearing deposits decreased $26.7 million and interest-bearing deposits increased $216.0 million during the three months ended March 31, 2023. The increase in deposits was due to a $161.4 million net increase in brokered deposits and a $123.3 million increase in retail and commercial accounts partially offset by a $95.3 million seasonal decrease in municipal deposits. During the three months ended March 31, 2023, the Company utilized a portion of its contingency funding sources and added $166.9 million of longer-term callable brokered CDs to improve its on-balance sheet liquidity position and mitigate risk to higher rates. The Company has the option to call the CDs after an initial three or six month period.
The deposit base consisted of 48.6% retail accounts, 33.2% commercial accounts, 12.5% municipal relationships and 5.7% brokered deposits at March 31, 2023. At March 31, 2023, 76.6% of deposits were fully insured by the FDIC while $757.4 million or 23.4% of total deposits were not insured by the FDIC. In addition, at March 31, 2023 $292.0 million in letters of credit were pledged as collateral for municipal deposits. As an additional resource to our uninsured depositors, we offer all depositors access to IntraFi's CDARS and ICS programs which allows deposit customers to obtain full FDIC deposit insurance while maintaining their relationship with our Bank.
During the three months ended March 31, 2023, the Company utilized a portion of its available line at the FHLB and increased its long-term debt $25.0 million due to favorable pricing on the borrowings versus alternative funding sources.
In addition to deposit gathering and our current long term borrowings, we have additional sources of liquidity available such as overnight borrowings from the FHLB, the Federal Reserve’s Discount Window and Borrower-in-Custody (BIC) program, correspondent bank lines of credit, brokered deposit capacity and unencumbered securities. Although we do not plan to access the Federal Reserve's Bank Term Funding Program (BTFP), we have $391.0 million of borrowing capacity based on the par value of unencumbered securities available as collateral under this line. At March 31, 2023, we had $1.7 billion in additional liquidity representing 45.7% of total assets and 51.9% of total deposits. For additional information on our deposit portfolio and additional sources of liquidity see the tables on page 14.
The Company maintained its well capitalized position at March 31, 2023. Stockholders' equity equaled $328.6 million or $45.96 per share at March 31, 2023, and $315.4 million or $44.06 per share at December 31, 2022. The increase in stockholders’ equity from December 31, 2022 is primarily attributable to net income and a decrease to accumulated other comprehensive loss (“AOCI”) resulting from a reduction in the unrealized loss on available for sale securities. The net after tax unrealized loss on available for sale securities included in AOCI at March 31, 2023 and December 31, 2022 was $43.5 million and $52.0 million, respectively.
Tangible stockholders' equity, a non-GAAP measure1, increased to $37.09 per share at March 31, 2023, from $35.19 per share at December 31, 2022. Dividends declared for the three months ended March 31, 2023 amounted to $0.41 per share, a 5.1% increase from the 2022 period, representing a dividend payout ratio of 39.0%. During the three months ended March 31, 2023, 16,573 shares were purchased and retired under the Company’s common stock repurchase plan at an average price per share of $49.79. In response to market volatility and economic uncertainty, the Company has temporarily suspended its stock repurchase plan to preserve capital.
ASSET QUALITY REVIEW
Asset quality metrics remained strong and continued to improve. Nonperforming assets were $1.9 million or 0.07% of loans, net and foreclosed assets at March 31, 2023, compared to $4.1 million or 0.15% of loans, net and foreclosed assets at December 31, 2022. As a percentage of total assets, nonperforming assets improved to 0.05% at March 31, 2023 compared to 0.12% at December 31, 2022. The decrease in nonperforming assets was due to the reclassification of troubled debt restructurings due to a change in accounting guidance, reduced levels of loans 90 days or more past due and still accruing, collection activities, and a decline in nonaccrual loans as a result of a sizable principal reduction on a commercial real estate loan. At March 31, 2023 the Company had no foreclosed properties.