Former United midfielder Beckham is now a co-owner of American club Inter Miami, estimated to be Major League Soccer’s most valuable franchise at $1.45bn (£1.07bn).
The 51-year-old, who was knighted in November, is also a brand ambassador for companies such as Adidas and Hugo Boss.
Victoria Beckham’s wealth has primarily been generated from her fashion label, having originally found fame as a member of the Spice Girls.
Promoters Barry and Eddie Hearn have joined Britain’s billionaire club, with their combined wealth estimated at £1.035bn.
Barry Hearn is the founder and president of Matchroom Sport, one of the leading promoters across boxing, darts and snooker.
His son Eddie is Matchroom’s chairman and promotes British boxer Anthony Joshua, who is the eighth highest sports figure on the list with £240m, one spot above his heavyweight rival Tyson Fury (£162m).
Seven-time F1 champion Sir Lewis Hamilton is fifth (£435m) while England football captain Harry Kane and two-time Wimbledon champion Sir Andy Murray are joint 10th (£110m).