Shares of companies with sports betting operations were hit hard Monday, after Major League Baseball's Miami Marlins were forced to postpone their home opener after 14 players tested positive for the coronavirus. The Philadelphia Phillies, the team that just played the Marlins, postponed their game Monday against the New York Yankees. That raised fears that many other games, if not the entire MLB season, might be shuttered if more players test positive for COVID-19. Shares of DraftKings Inc. tumbled 8.7%, MGM Resorts International /zigman2/quotes/209932643/composite MGM +3.93% shed 6.0%, Penn National Gaming Inc. /zigman2/quotes/209264611/composite PENN +2.51% dropped 6.9%, Las Vegas Sands Corp. /zigman2/quotes/208792014/composite LVS +2.92% fell 2.1% and Wynn Resorts Ltd. /zigman2/quotes/208845907/composite WYNN +4.61% lost 4.2%. The selloff comes while the S&P 500 /zigman2/quotes/210599714/realtime SPX +0.99% rallied 0.6%.