amounted to $19.9 million, or 0.9%, of total commercial loans, including $873,000 in PPP loans. We provided deferrals for loans in this sector with outstanding principal balances of $15.5 million.
We provided access to the PPP to both our existing customers and new customers, to ensure small businesses in our communities have access to this important lifeline for their businesses. During the first quarter of 2021 we originated $81.6 million in PPP with processing fees of $3.9 million and processed forgiveness on $43.9 million loans. As of March 31, 2021, PPP loans amounted to $164.3 million and there was $5.0 million in deferred processing fee income that will be recognized over the life of the loans.
We are also working with commercial loan customers that may need payment deferrals or other accommodations to keep their loans out of default through the COVID-19 pandemic. As of March 31, 2021, we have 169 payment deferrals on commercial loans with a total principal balance of $301.8 million, or 13.9%, of total commercial loans, of which $219.0 million are loans included in an at-risk sector. As of March 31, 2021, 89.1% of the commercial deferrals have expired and the borrower is making payments as agreed, 0.01% of the commercial deferrals have expired and the borrower is delinquent, and 10.8% are in active deferral period. The active commercial deferrals expire during 2021. We continue to consider requests for additional deferrals or new deferrals at March 31, 2021 for commercial credits.
The residential loan and consumer loan portfolios have not experienced significant credit quality deterioration as of March 31, 2021; however, the continuing impact and uncertain nature of the COVID-19 pandemic may result in increases in delinquencies, charge-offs and loan modifications in these portfolios through the remainder of 2021. As of March 31, 2021, we had 163 payment deferrals on residential mortgage loans with a total principal balance of $46.1 million, or 4.3% of total residential loans, of which 88.9% of the deferrals have expired and are paying as agreed, 3.2% have expired and are delinquent and 7.9% are in active deferral periods. We had 434 payment deferrals on consumer loans with a total principal balance of $10.3 million, or 4.5%, of total consumer loans, of which 93.6% of the deferrals have expired and are paying as agreed. Requests for additional extensions on residential mortgage loans and consumer loans were not significant as of March 31, 2021.
Net charge-offs totaled $102,000 for the quarter ended March 31, 2021, or 0.01%, of average loans outstanding on an annualized basis, compared to $1.4 million, or 0.16% of average loans outstanding on an annualized basis, for the quarter ended December 31, 2020 and $1.4 million, or 0.18%, of average loans outstanding on an annualized basis, for the quarter ended March 31, 2020. Net-charge offs for the quarter ended December 31, 2020 included a charge-off in the amount of $937,000 recorded on the sale of two nonperforming commercial loans and net charge-offs for the quarter ended March 31, 2020 included a $1.2 million charge-off on a commercial real estate loan.
Credit quality performance has remained strong with total nonperforming assets of $32.9 million at March 31, 2021, compared to $34.7 million at December 31, 2020 and $32.1 million at March 31, 2020. The decrease in nonperforming assets from the preceding quarter reflects a $1.0 million decrease in nonperforming residential real estate loans. Nonperforming assets as a percentage of total assets were 0.71% at March 31, 2021, 0.77% at December 31, 2020, and 0.78% at March 31, 2020.
Balance Sheet
Total assets increased $122.3 million, or 2.7%, to $4.61 billion at March 31, 2021 from $4.48 billion at December 31, 2020. The increase primarily reflects an increase of $107.4 million in short-term investments and a $27.7 million increase in securities available for sale.
Net loans decreased $33.2 million, or 1.00%, to $3.41 billion at March 31, 2021 from $3.44 billion at December 31, 2020. The net decrease in loans for the three months ended March 31, 2021 was primarily due to decreases in consumer loans of $45.6 million and residential real estate loans of $43.6 million, partially offset by increases in commercial and industrial loans of $35.3 million, commercial construction loans of $12.9 million and commercial real estate loans of $7.8 million. The allowance for loan losses was flat at $55.4 million at March 31, 2021 and December 31, 2020.
Total deposits increased $168.4 million, or 4.8%, to $3.67 billion at March 31, 2021 from $3.51 billion at December 31, 2020. Compared to the prior quarter, non-certificate accounts increased $204.2 million and term certificate accounts decreased $35.9 million. FHLB borrowings decreased $51.6 million, or 34.6%, to $97.5 million at March 31, 2021 from $149.1 million at December 31, 2020.
Total stockholders’ equity was $698.1 million at March 31, 2021, compared to $696.3 million at December 31, 2020 and $675.1 million at March 31, 2020. The Company adopted a share repurchase program on September 3, 2020 to repurchase up to 2,920,900 shares of the Company’s common stock, or approximately 5% of the Company’s outstanding shares. The Company repurchased 1,202,730 shares at an average cost of $12.13 per share in the first quarter of 2021 and 1,533,500 shares in the fourth quarter of 2020 at an average cost of $10.27 per share, recorded in treasury stock on the balance sheet. The Company adopted a second share repurchase program on April 16, 2021 to repurchase up to 2,790,903 shares of the Company’s common stock, or approximately 5% of the Company’s outstanding shares pending a non-objection from the Federal Reserve Bank of Boston. The tangible common equity to tangible assets ratio was 13.77% at March 31, 2021, 14.11% at December 31, 2020, and 14.90% at March 31, 2020. At March 31, 2021, the Company and the Bank had strong capital positions and exceeded all regulatory capital requirements.