Sports Direct’s acting finance director has left the company nearly a week after it issued a profit warning.

The troubled retailer announced that Matt Pearson had resigned to take up a role with a different employer. He will stay at Sports Direct until the end of December.

His departure comes a few weeks after the chief executive, Dave Forsey, stepped down unexpectedly, prompting Sports Direct’s billionaire founder, Mike Ashley, to take the reins.

The company has appointed Herbert Monteith, a member of the finance team, as interim head of finance, a non-board position. He will work closely with Karen Byers, who was recently promoted to global head of operations, and Sean Nevitt, the global head of commercial.

Ashley said: “Matt has been a valued member of the Sports Direct family for more than nine years and he will be a loss to the company. I wish him all the best for the future and would like to thank him for his time at Sports Direct.”

At the end of last week, Sports Direct said the “flash crash” of sterling had caused the company to lose £15m in the currency markets. On Thursday, it said trading remained in line with that announcement.

The retailer has faced stern criticism over its treatment of workers and issued a series of earnings downgrades, which were blamed on tough trading conditions.

Pearson was promoted to acting CFO in June 2015 after the position had been left vacant for 18 months. Some City investors had expressed concern that Sports Direct was operating without a permanent finance chief.