The deal between Guy Hands, head of current owners Terra Firma, and Truell, was struck earlier this week.
A report in The Telegraph said the sale price was “significantly less” than the £225 million paid for the company by Hands – then working for Nomura International – in 2000.
Hands took the business with him when he left Nomura to set up Terra Firma in 2002, and is thought to have made a profit on the deal through selling shop freeholds in leaseback deals over the past three years.
Thresher Group would not comment on the details of the deal with Truell, but is expected to release a statement within the next few days.
Truell is the founder of Duke Street Capital, a private equity firm that has been investing in UK and French businesses since the 1980s.