Shares in Worldpay have soared by more than 23% after it confirmed speculation of a takeover swoop from US rival Vantiv and banking giant JPMorgan Chase.
The global payments processor has received a preliminary approach from the two firms, but said it did not mean a formal offer would be made.
Worldpay's stock value rocketed during morning trading on the London Stock Exchange (LSE), valuing the company at more than £7 billion.
In a statement, Worldpay said: " There can be no certainty either that an offer will be made nor as to the terms of any offer, if made.
"This announcement has been made without the consent of Vantiv or JPMorgan."
Worldpay has 400,000 customers worldwide and was owned by the Royal Bank of Scotland until the state-backed lender sold off its remaining stake to private equity firms Advent International and Bain Capital in 2013.
The company later sealed the biggest floatation of 2015 when it listed on the LSE with a valuation of £4.8 billion.
The approach from Vantiv and JP Morgan would see the two companies snap up Worldpay's entire issued, and to be issued, share capital.
They now have until August 1 to firm up their approach, according to takeover rules.
Vantiv is a payment processor based in Cincinnati, Ohio,handling 25 billion transactions worth 920 billion US dollars (£711 billion) last year.