Online rail ticketing company, Trainline, hopes to raise £75m by listing its shares on London's stock exchange.
The site said the flotation cash would help to build its profile and pay for growth plans.
The company is expected to float in June and will issue new shares to generate the additional funds.
Trainline is currently owned by US private equity house KKR, which bought the site in 2015 for £500m.
The firm's owners think it could be worth up to £1.5bn, according to the Financial Times.
Biggest this year
The valuation will not be known until the shares are priced nearer the time of the listing, but it is expected to be one of the biggest flotations of the year.
Just 39% of all rail tickets were bought online in Europe's five largest markets last year, which Trainline boss Clare Gilmartin sees as an opportunity for further growth.
She said the firm was also looking to benefit from from government drives to increase train travel.
Trainline employs more than 600 people across its offices in London, Paris and Edinburgh and sells tickets on behalf of 220 transport providers in 45 countries.
The company reported revenue of £210m for last year as ticket sales climbed by almost a fifth to £3.2bn.
This is the second time Trainline has been expected to float on the stock exchange. Before a sale was agreed to KKR, the firm's private equity owners said they wanted to raise £75m by seeking a very similar listing.
The market for online train tickets is not particularly crowded and in 2016 Trainline acquired its French rival Captain Train for £110m.
Trainline started life in 1997 as a division of Virgin Rail, selling tickets through a call centre.