The parent company of specialist operator Great Rail Journeys is tipped to be about to be sold for £50 million.
Buyout firm ECI is reported to have entered exclusive talks to acquire Amber Travel Partnership.
The travel business is being sold by rival private equity firm Primary Capital which hired KPMG last year to find a buyer for the business, the Sunday Times reported.
Aito member Great Rail Journeys, based in York, has been established for more than 30 years and provides 230 tours in 40 countries.
Primary Capital acquired Amber Travel Partnership, which also included Inntravel, in 2005. Inntravel was sold to Inghams three years later.