Shares headed toward a seven-year low after the sportswear retailer delayed publishing its results as auditors increase their scrutiny of its accounting.
Billionaire Mike Ashley's current direct and indirect holdings include Debenhams, House of Fraser and French Connection, among others.
The plan to save the high street includes reduced rent, waived business rates and a levy on e-commerce sales.
The sportswear group has agreed to buy the freehold of the Glasgow's Frasers department store, which trades as part of the House of Fraser business, for £95 million.
Shares in Debenhams rose after an outgoing director of Sports Direct said theboard had discussed combining the department store group with House of Fraser.