It would seem the answer is a very great deal, indeed - particularly if they are at the top of the tree.
Take, for instance, Pat Eddery, the flat race jockey. He appears to earn a terrific amount of money and must surely be one of the highest paid sportsmen in the UK, by Bunhill's reckoning.
When you consider that for much of the year a flat race jockey is not riding, the sums become even more fantastic.
In 1988 Eddery received nearly pounds 900,000 for what is termed in his accounts 'the provision of jockey services' (that is, riding horses). Then in 1992 his company, Patrick Eddery Ltd, reported a turnover of pounds 1.1m, with a retained profit of nearly pounds 700,000.
Piggott's legendary meaness may have been overtaken, for a note to Eddery's accounts reveals a charitable donation of pounds 350.
And what is this I spot? Note 12 states: 'A loan subsisted and was made to a director during the year which is in contravention of the Companies Act 1985.' Oh dear, oh dear.