McCarthy & Stone claims 3.5 million people are interested in buying a retirement home.
Goldman Sachs, Deutsche Bank and Jefferies are the bookrunners on the float.
Equiniti, which administers shares and pensions for firms such as Marks & Spencer and Royal Mail, set the price range for its float today, giving the firm a value of between £495 million and £600 million.
Equiniti’s float will be open to retail investors willing to buy a minimum £1000 of shares.
The firm will use part of the £315 million proceeds to pay down debt.