Italian fashion house Valentino aims to sell around a quarter of the company in an initial public offering (IPO) which will not take place before the second half of 2018, a source close to the matter said.

The group, founded in 1960 by Italian designer Valentino Garavani, is owned by Mayhoola for Investments, a Qatari investment vehicle which bought it in 2012 from private equity firm Permira for around 700 million euros (£618.3 million).

Valentino's owners started looking into a possible market listing in late 2015 but the operation has been postponed year after year.

The source told Reuters that the IPO process had not kicked off yet and listing would only happen where market conditions would be favourable as the move was not dictated by any liquidity needs.

"Mayhoola intends to carry out this operation as it wants to accredit itself in the world of finance, bringing to the market a company that is expected to gain even more value once it is floated," the source said.

Valentino would list on the Milan bourse's main market, the MTA, which requires at least 25 percent of a company's capital to be floated.

Valentino declined to comment, Mayhoola was not immediately available for a comment.

The group, known for its trademark bright red dresses, posted 2016 sales of 1.1 billion euros and core profits of 206 million euros. Chief Executive Stefano Sassi said in June he hoped for a double-digit growth in sales this year.