BOSTON—The world’s 20 best-performing hedge funds earned $65.4 billion for clients in 2021, setting a new record as stock markets marched higher despite rising prices and coronavirus cases, LCH Investments data show. As a group, the most successful managers earned more than one third of the $176 billion that all hedge funds made last year, LCH Investments, a fund of funds firm that tracks returns and is part of Edmond de Rothschild group, reported. The top 20, including brand-name investment firms TCI Fund Management and Citadel, returned an average 10.5 percent and jointly managed nearly one fifth of the industry’s $3.6 trillion in assets, the data show. Their returns, however, lagged broader stock market gains. The best performers in 2021 topped the $63.5 billion they made in 2020 and 2019’s $59.3 billion, despite the Delta and Omicron coronavirus variants and fears the U.S. Federal Reserve will soon have to raise …