The Russian tycoon working on a bid for Waterstone's bookshops could collect $1.65bn (£1bn) when Russia's largest phone retailer Euroset floats on the London stock market this month.
Alexander Mamut owns 50.01% of Euroset, and has said in the past he could sell his entire stake. An announcement from Euroset said it could raise up to $140m in a flotation that will value the company at between $2.7bn and $3.3bn.
Mamut is working with Tim Waterstone on a bid for the chain that bears the latter's name after struggling parent HMV put the business on the auction block in an attempt to cut its debts of £130m.
The Russian millionaire and Waterstone have been assembling a management team with the intention of returning Waterstone's to its roots as a stock holding book chain with more day-to-day management input from staff.
Mamut owns 6% of HMV and is understood to be taking advice from bankers at Credit Suisse. He was previously an adviser to former Russian president Boris Yeltsin, and was a friend of Yeltsin's daughter Tatyana Dyachenko.
HMV chief executive Simon Fox is in talks with the retailer's banks about relaxing the terms of its loans. He has admitted to neglecting Waterstone's, which has more than 300 branches, to concentrate on saving HMV, which has struggled as sales of CDs and DVDs go into freefall.
Fox has expanded into live music as well as forging a tie-up with Curzon cinemas, and devoted space in its stores to mobile phones and technology. But that has not prevented two profit warnings this year.
Funds raised in the Euroset float would be spent on adding to its 4,300 outlets in Russia, Ukraine and Belarus. Analysts expect a move into Poland and Slovakia. The company is being advised by Goldman Sachs, Credit Suisse, Alfa Capital and VTB Capital, and plans to hold an investors' roadshow in the US, UK and Europe.
The other main shareholder of Euroset with more than 49% is VimpelCom, one of Russia's top three mobile phone operators. VimpelCom says it intends to hold on to its stake. Euroset was founded by billionaire Russian businessman Yevgeny Chichvarkin who went into a self-imposed exile in Britain in 2008, saying he faced imprisonment in Russia.
