Worldpay's shares had started rising before the announcement, with traders citing rumours the company may be a bid target.
Vantiv and JP Morgan now have until August 1 to announce firm intentions to buy or else walk away. Neither company could be reached for comment in the USA, which is marking the July 4 holiday.
Vantiv has made numerous acquisitions in the area of payments.
Shares in the payments processing firm Worldpay have jumped 15% after the company said it had attracted takeover interest.
A spokeswoman for JPMorgan in London declined to comment. Banks and payment companies are racing to retool their offerings as customers increasingly turn to card and mobile devices to pay for goods.
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One of these such shooters could be Joe Ingles , a restricted free agent that should command sizable offers from other teams. In the event Hayward leaves, head coach Quin Snyder will probably want to shift toward more of a point guard-centric attack.
Over the weekend Danish card payment services company Nets A/S said it had been approached by potential buyers, which market observers say could involve established payment giants Mastercard or Visa.
It says that on a typical day it processes more than 31 million mobile, online and in-store transactions, or around 400 a second.
A deal with JPMorgan Chase would add to the processing power of the bank's debit and credit card businesses. While the bank has made a series of smaller financial technology acquisitions in recent years, it has so far held off from big-ticket deals.
It was spun out of the Royal Bank of Scotland in late 2010 and sold to private equity companies Bain Capital and Advent International. Sources close to the company said the offers were unsolicited.
Worldpay has had its share of headlines around malicious hacking of its services but it has also been making moves to position itself at what it believes could be some of the newer frontiers in payments, such as developing a prototype for VR payments, and a secure, smartphone-based payment service that works using the camera's contactless chip reading functionality and an app - no extra hardware required.