 BOSTON--BUSINESS WIRE--Advent Technologies Holdings, Inc. NASDAQ: ADN Advent, an innovation-driven company in the fuel cell and hydrogen technology space, today announced that it will release its financial results for the first quarter ended March 31, 2021 on Thursday, May 20, 2021 and will host a conference call the same day, Thursday, May 20, 2021, at 9:00 AM ET to discuss its results. To access the call please dial 866 498-0631 from the United States, or 873 415-0202 from outside 