Online rail booking site Trainline is being tipped for a stock market flotation.
The company is understood to have started discussions with banks about an initial public offering that could value it at more than £400 million, Sky News reported.
Exponent Private Equity, which has held a controlling stake in Trainline since 2006, is expected to appoint City advisers to oversee a flotation within weeks, although the timing of any listing is uncertain and an outright sale to another investor is a possibility, sources said.
Trainline made around £9 million profit in the year to March 2013, despite having to pay £2 million in fees to advisers who led an unsuccessful sale process.
The recent performance has been strong, and Exponent is understood to believe it possesses a sufficiently visible growth profile to reassure prospective investors, according to the Sky News report. Neither company would comment.
The business, which handles ticket sales for the majority of UK rail operating companies, added two million customers in the year to March and has seen its digital app downloaded more than six million times since its launch.
The company also said that its site was the most popular travel app on iPhone and Android devices.
Established in 1999, Trainline was bought by Exponent for about £160 million from a consortium which included Virgin, Stagecoach and National Express.
A previous attempt to sell the business in 2012 collapsed when bidders including Priceline.com and a Canadian pension fund declined to meet the asking price.
As well as its own website, Trainline runs digital sales operations for the majority of train operating companies and has expanded overseas, serving major companies and travel agents as clients.