British payments firm Worldpay Group Plc said the deadline for its U.S. suitor Vantiv Inc. to make a firm takeover offer for the company has been extended for a second time.

Vantiv is now required to clarify its intentions by no later than 5 p.m. London time on Aug. 11. The new deadline may be further extended with the consent of the U.K. Takeover Panel, the company noted. Worldpay added that "positive discussions" with Vantiv are continuing.

As a result of the ongoing negotiations, the publication of Worldpay's half-year results was postponed to Aug. 9, when Vantiv's second-quarter results will also be released.

The two companies reached an agreement on the key terms of a potential merger in early July. The initial deal would see Worldpay's shares delisted from the London Stock Exchange, with a view to create hubs in the U.K., Europe and the U.S.

The extension follows the departure of Peter Jackson, CEO of Worldpay's British division, to join online betting operator Paddy Power Betfair Plc.

Jackson took over the helm of Worldpay U.K. in March.