The Indian steel magnate holds a 20 per cent stake in the Championship side and is worth an estimated £18.4billion.
Mittal is topping the 2009 FourFourTwo.com Rich List ahead of Manchester City owner Sheikh Mansour bin Zayed al Nahyan.
The City owner has a fortune of £17billion.
Chelsea’s Russian owner Roman Abramovich has a fortune of £7.8billion and comes third in the ranking.
