US private equity major KKR said it has acquired British rail ticket website thetrainline.com from buyout firm Exponent for an undisclosed sum, just weeks after the retailer of train tickets announced plans for an initial public offering.
KKR's move will reportedly derail the online rail ticket booking firm's planned London stock market floatation, which Reuters said could have valued the firm at over £500m ($758m, €652m).
Trainline is licensed to sell rail tickets on behalf of all UK train operating companies, the Deutsche Bahn and Trenitalia.
Buyout firms, at times, prefer to sell a company, rather than list it on a stock exchange, because it allows them to exit their investment speedily.
KKR, when announcing the deal, said in a statement: "Trainline is the most downloaded travel app in the UK and its website ranks 5th by gross transaction value in the UK e-commerce sector. The company has 4.7m active customers, 20.8m visits per month and operates platforms for both consumers and businesses."
Dominic Murphy, member and head of KKR operations in the UK said: "The investment in Trainline adds to our track record of partnering with entrepreneurs and management teams to build global companies and industry leaders.
"Similar to our Alliance Boots investment, we will support a strong investment program leading to a further transformation and strong international expansion of the company."
Trainline CEO Clare Gilmartin commented: "Trainline has achieved a lot during our eight years working alongside Exponent to develop the business, and we are well positioned to capitalise on great growth opportunities driven by the systemic shift to online in rail and the step-change in mobile and e-fulfilment, as well as international opportunities.
"In KKR we have found a partner that can support our expansion with capital, operational resources and access to its global network."
London-based Exponent Private Equity acquired Trainline in 2006 for nearly £160m from a consortium that included Virgin, Stagecoach and National Express.
Adjusted core earnings (EBITDA) across Trainline's branded businesses rose to £21m in 2014, from £14.3m in the preceding year.
Trainline was established in 1999.