Britain’s largest book chain, Waterstones, has been acquired for an undisclosed sum by the hedge fund Elliott Advisors.

James Daunt, who has been chief executive of Waterstones since 2011 and who presided over an 80% jump in annual profits in the year to April 2017, will remain in his position following the sale, along with his “key leadership team”.

The chain, which has 283 stores, was put up for sale last year by its owner, the Russian billionaire Alexander Mamut. Exclusive talks with Elliott began in late January. Mamut’s firm, Lynwood Investments, which has owned Waterstones since 2011, will retain a minority stake in the business. The deal is expected to be completed in early May.

Daunt hailed the acquisition was “definitely a good thing” for the chain, a vindication of “good old-fashioned bookselling”, stressing that there were no closures or job cuts planned as a result. “Quite the opposite – we’re very much in expansion mode, we’re opening up new shops,” he said.

“By the end of the year we’ll have more shops not less, and next year an awful lot more shops … For the last year we’ve been pretty distracted with this whole process but have managed to keep going at a reasonable clip – hopefully we will now get on with it with a bit more focus. There’s plenty of room to grow – there are plenty of very nice towns and high street and even shopping centres which don’t have bookshops and should, and we will be very happy to put them there.”

Paul Best, head of European private equity at Elliott, which has funds under management of around $35bn (£25bn), said the firm would be “supporting James Daunt and his entire team over the long term as they continue to build and grow the business”.

“As the leading physical book retailer in the UK, Waterstones is a mainstay of UK high streets and has a huge and loyal customer base,” said Best.

After the demise of household names such as Borders, Dillons and Ottakars, Waterstones’ almost 300 shops make it the only specialist bookseller on the UK high street with the scale to challenge the might of Amazon. When Mamut acquired Waterstones from HMV in 2011, for £53m, the chain had not made an annual profit since 2008. He brought in Daunt, the founder of the independent London book chain Daunt Books, to run the company. Daunt has taken a hands-off approach, allowing local shops to develop their own ranges and displays rather than dictating a uniform approach from head office. In 2016 Waterstones made its first annual profit since 2008, after Mamut invested around £100m in the business, and as physical book sales saw a resurgence and ebooks plateaued.

Daunt said today that the chain “would have gone under” without Mamut’s 2011 intervention. “Come 2015 when ebooks started to drop away again, we began to really prosper,” he said, “but it took nerve.”

The chain’s survival, said Daunt, is essential to the health of the UK book trade. “It would be a very different sort of literary landscape without Waterstones,” he said. “You need a strong Waterstones within the trade – [it] happens to be the last remaining bookseller of any substance.”

“Most ‘proper books’ are sold at Waterstones on the high street, and if you didn’t have Waterstones you’d have very few independents – lovely independents, but very few, not giving much access to books to many. And then you’d have Amazon, which is a very different sort of a place, no curation, no selection, no championing of authors and individual books, and without it the trade as a whole would be a very much less vibrant place.”

According to the award-winning novelist Jeanette Winterson, bookshops aren’t just selling “stuff”, they’re selling “soul”.

“That’s why readers resisted the e-format,” she told the Guardian, “and why the non-readers who predicted the end of print couldn’t understand that the physical object of a book is so much more to a reader than just format.”

Bookshops are a “civilising presence” on the high street, she continued. “There is more to life than fast food, fast fashion and pound shops. For me, a bookshop is about different values, about the life of the mind, and a cultural space too. The best bookshops around the world are run or owned by book lovers. If Waterstones messes with that simple truth it will fold.”