Mike Ashley is understood to be facing an investigation into possible loans secured from Icelandic bank Kaupthing.
Reports suggest that the Sports Direct founder could be investigated as part of a probe by the Serious Fraud Office (SFO) into the failed Icelandic bank Kaupthing.
Ashley was a depositor in some of the banks and the SFO is understood to have plans to look into whether he also took out loans.
It may also look at whether Chris Ronnie, who was formerly chief executive of rival JJB, could have indirectly received some of the loans.
Sports Direct is also being investigated by the SFO alongside separate investigations by the Office of Fair Trading and the Competition Commission.