Holidays-to-insurance company Saga is planning to list its shares on the London Stock Exchange.
Growing older doesn't have to be uncool
The family-run firm, which targets the over-50s, had also been considering a sale to private investors.
Earlier estimates for the initial public offering said that the value of the sale could be in excess of £1bn.
Kent-based Saga is being sold after chairman Roger De Haan announced his retirement. The company was founded in 1951 as a single hotel in Folkestone.
Today, it specialises in a wealth of services for the over-50s and has almost 8 million people on its books.
Saga also has a best-selling magazine, offers health advice, and runs a number of radio stations.
"We are very pleased with the level of interest shown by customers and other members of the public in registering their interest in participating in the possible IPO," said Andrew Goodsell, Saga's chief executive officer.
"Looking forward, I believe that Saga is well positioned to benefit from a demographic shift, which expects to see its target market increase by 5 million people over the next 20 years."