Swansea's Ashley Williams clashed with Hull's Tom Huddlestone and Yannick Sagbo in the closing stages of their 1-1 on December 9, sparking a fracas between both teams' players.
"The clubs each admitted a charge of failing to ensure that its players conducted themselves in an orderly fashion," the FA said in a statement.
Hull, who are 12th in the Premier League, travel to West Bromwich Albion on Saturday and 10th-place Swansea play Everton on Sunday.
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