The private-equity backers of Legoland owner Merlin Entertainments will sell a larger-than-expected share of their stake when the company completes an initial public offering next month.

In a statement to the London Stock Exchange Wednesday, the company said it is now targeting a free float of 20% to 30%, up from at least 20% previously guided, and said the shares would be priced at between 280 pence a share to 330 pence a share, valuing the company at £2.86 billion ($4.59 billion) to £3.34 billion.