The small- to medium-sized businesses that we lend to may have fewer resources to weather adverse business developments, which may impair our borrowers’ ability to repay loans.
As of March 31, 2021 and December 31, 2020, we had approximately $3.9 million and $4.0 million of commercial and industrial loans to businesses, respectively, which represents approximately 1.9% and 1.7%, respectively, of our total gross loan portfolio held-for-investment. We also have approximately $10.8 million and $5.2 million, or 5.2% and 2.1% of our total gross loans held-for-investment, in SBA loans that are commercial and industrial loans to businesses as of March 31, 2021 and December 31, 2020, respectively. Small- to medium-sized businesses frequently have smaller market shares than their competition, may be more vulnerable to economic downturns, often need substantial additional capital to expand or compete and may experience substantial volatility in operating results, any of which may impair a borrower’s ability to repay a loan. In addition, the success of a small- and medium-sized business often depends on the management skills, talents and efforts of a small group of people, and the death, disability or resignation of one or more of these people could have a material adverse effect on the business and its ability to repay its loan. If our borrowers are unable to repay their loans, our business, financial condition and results of operations could be adversely affected.
Our concentration of large loans to a limited number of borrowers may increase our credit risk.
As of March 31, 2021 and December 31, 2020, our 10 largest borrowing relationships accounted for approximately 20.3% and 16.0%, respectively, of our total gross loans held-for-investment. Along with other risks inherent in these loans, such as the deterioration of the underlying businesses or property securing these loans, this high concentration of borrowers presents a risk to our lending operations. If any one of these borrowers becomes unable to repay its loan obligations because of economic or market conditions, or personal circumstances, such as divorce or death, our nonaccrual loans and our allowance for loan losses could increase significantly, which could have a material adverse effect on our assets, business, financial condition and results of operations.
We have loan concentrations in our SBA 7(a) loan portfolio related to the financing of professional, scientific and technical services (including law firms) non-store retailers (e-commerce), and ambulatory healthcare services
Loan concentrations are considered to exist when there are amounts loaned to a multiple number of borrowers engaged in similar activities that would cause them to be similarly impacted by economic or other conditions. As of December 31, 2020, our loan portfolio included approximately $9.4 million of loans, or approximately 3.6% of our total loans outstanding, to professional, scientific and technical services (including law firms), $7.2 million of loans, or approximately 2.8% of our total loans outstanding, non-store retailers (including e-commerce), and $4.2 million of loans, or approximately 1.6% of our total loans outstanding, to ambulatory healthcare service businesses. As of March 31, 2021, our loan portfolio included approximately $9.9 million of loans, or approximately 4.0% of our total loans outstanding, to professional, scientific and technical services (including law firms), $7.9 million of loans, or approximately 3.2% of our total loans outstanding, non-store retailers (including e-commerce), and $4.2 million of loans, or approximately 1.7% of our total loans outstanding, to ambulatory healthcare service businesses. We had $17 thousand in charge-offs during 2020 and $17 thousand in charge-offs for the three month period ended March 31, 2021, respectively, in our professional, scientific and technical services (including law firms) non-store retailers (e-commerce), and ambulatory healthcare services portfolio assets. We believe that these loans are conservatively underwritten to credit worthy borrowers and are diversified geographically. However, to the extent that there is a decline in professional, scientific and technical services (including law firms), non-store retailers (e-commerce), and ambulatory healthcare services industries in general, we may incur significant losses in our loan portfolio as a result of these concentrations.
A lack of liquidity could impair our ability to fund operations and adversely impact our business, financial condition and results of operations.
Liquidity is essential to our business. We rely on our ability to generate deposits and effectively manage the repayment and maturity schedules of our loans and investment securities, respectively, to ensure that we have adequate liquidity to fund our operations.
Our most important source of funds is deposits. As of March 31, 2021 and December 31, 2020, approximately $100.8 million and $88.1 million, or 53.5% and 53.5%, respectively, of our total deposits were noninterest bearing demand accounts. These deposits are subject to potentially dramatic fluctuations due to certain factors that may be outside of our control, such as a loss of confidence by customers in us or the banking sector generally, customer perceptions of our financial health and general reputation, any of which could result in significant outflows of