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Exhibit 99.1 PRESS RELEASE April 21 , 2021 , 8:00 AM ET Contact : Jeff W. Dick , Chairman & CEO ( 703 ) 481-4567 MainStreet Bancshares , Inc. Reports Strong First Quarter 2021 Earnings Fairfax , Virginia – April 21 , 2021 - MainStreet Bancshares , Inc. ( Nasdaq : MNSB & MNSBP ) , the holding company for MainStreet Bank , reported net income of $ 5.5 million for the first quarter of 2021. Net income of $ 5.5 million represents a 12.95 % Return on Average Equity ( ROAE ) , a 1.32 % Return on Average Assets ( ROAA ) and $ 0.65 per share of common stock ( basic and diluted ) . Net interest income was $ 13.5 million and noninterest income was $ 1.4 million for the quarter - ended March 31 , 2021 , an increase of 31 % and 2 % respectively over the same period in 2020. One - half of the increase in net interest income for the quarter came from Paycheck Protection Program ( PPP ) origination fees . The Company's cost of funds for the quarter - ended March 31 , 2021 was 1.11 % , down from 2.11 % from the same period a year ago . The Company is focused on reducing funding costs , increasing fee income , and improving operating efficiency . The Company's efficiency ratio was 52 % for the quarter - ended March 31 , 2021 , a solid improvement from the 61 % efficiency ratio reported for the same period a year ago . Total assets were $ 1.7 billion on March 31 , 2021 , an increase of 31 % from March 31 , 2020. Net loans were $ 1.3 billion on March 31 , 2021 , which included $ 180 million in PPP loan balances . Asset quality continues strong with non - performing assets representing 0.08 % of total assets on March 31 , 2021 . Non - interest - bearing deposits represented 32 % of the $ 1.5 billion in total deposits on March 31 , 2021. Seventy - five percent of total deposits are core deposits – which is a significantly positive shift over the past eight quarters . The Company continues to be strongly capitalized , and on April 6 , 2021 , the Company entered into a Subordinated Note Purchase Agreement for a private placement of $ 30 million in aggregate principal amount of 3.75 % Fixed - to - Floating Rate Subordinated Notes due in 2031. The Company intends to use the net proceeds from the issuance of the Notes for general corporate purposes , including potential retirement of existing subordinated debt and capital to support the organic growth of its bank subsidiary , MainStreet Bank . Performance Trust Capital Partners , LLC served as sole placement agent for the offering . " With 2020 behinds us , our clients are starting this year strong and confident , ” said Abdul Hersiburane , President of MainStreet Bank . " We are focused on aggressively adding new loan and deposit relationships to the mix . " " We are fortunate to be in such a robust and resilient market , ” said Jeff W. Dick , Chairman & CEO of MainStreet Bancshares , Inc. and MainStreet Bank . " With the addition of $ 30 million of very low - cost subordinated debt to our capital stack , we are well positioned to pursue continued growth opportunities . " ABOUT MAINSTREET BANK : MainStreet operates seven branches in Herndon , Fairfax , Fairfax City , McLean , Leesburg , Clarendon , and Washington D.C. MainStreet Bank has 55,000 free ATMs and a fully integrated online and mobile banking solution . The Bank is not restricted by a conventional branching system , as it can offer business customers the ability to Put Our Bank in Your Office® . With robust and easy - to - use online business banking technology , MainStreet has “ put our bank ” in thousands of businesses in the metropolitan area .