Mike Ashley has accused former MP Iain Wright of slashing millions off Sports Direct's share price and sparking a rash of assaults on the retailer's staff, according to reports.
The allegations were part of a formal complaint to the Parliamentary Commissioner for Standards lodged earlier this week.
The firm blames Wright for the "media circus" that erupted after a Sports Direct factory was described as a "Victorian workhouse", according to a letter written by Sports Direct chairman Keith Hellawell which was seen by the Press Association.
Sports Direct said the number of hate calls received at its customer services team more than doubled following the incident.
“This coincided with a catastrophic fall in the share price of Sports Direct, which depleted tens of millions of pounds from the value of our share bonus pool for eligible staff," Hellawell wrote.
The complaint handed in earlier this week was said to deal with concerns that Wright had failed to explain a donation he had received from the Unite Union, which made the Victorian remarks at a committee hearing overseen by Wright in 2016.
Sports Direct did not immediately respond to a request for comment.