USA teams fill all the leading 10 spots -with six from the NFL, three in basketball's NBA and one in Major League Baseball.
Four-time Super Bowl winners the Giants come in at $7.3bn, just behind the New York Patriots on $7.4bn.
7 New York Giants, NFL - $7.3bn.
Now "The Money" has launched a buy-in bid for the New York Giants that is more jaw-dropping than any knockout blow he landed in the ring.
The boxing legend, 47, is reportedly heading a group trying to purchase 10% of the NFL team... for around $700 million (£556m).
