WASHINGTON, Aug 10 (Reuters) - The U.S. Federal Reserve announced Monday how much each large bank that underwent its 2020 stress tests will have to hold in additional capital.

The results mark the first time the Fed has given out custom capital requirements for each bank under its new "stress capital buffer," and takes effect on October 1. Goldman Sachs and Morgan Stanley were ordered to hold the most capital of the 34 firms tested, with ratios of 13.7% and 13.4% respectively. (Reporting by Pete Schroeder Editing by Chizu Nomiyama)