Roy Keane is the joint-second richest manager in the UK, despite being out of management since he was sacked from Ipswich in 2011.
Manchester United boss Alex Ferguson retained his position as the wealthiest football manager in Britain with a fortune of £34m, according to the Sunday Times Sport Rich List.
Arsenal manager Arsene Wenger and Keane, who now works as a pundit for ITV, are ranked joint second, worth £29m, ahead of Manchester City's Roberto Mancini (£21m).
The fourth annual guide to the wealthiest people in British sport rates Lewis Hamilton, now worth £60m, an increase of £5m since last year, as the wealthiest British driver currently competing in Formula One.
Hamilton stays narrowly ahead of Jenson Button, who has also added £5m to his fortune in the last year and is now worth £58m.