Visa is paying £198m to buy Earthport, a British firm that facilitates international transactions for banks and businesses, the US-based payments group said.
Visa International Service Association, a unit of Visa, has offered 30 pence for each Earthport share, a price that is four times the stock's Monday closing price of 7.45 pence.
Earthport shares surged in early trading on Thursday and matched the offer price.
The London-headquartered firm said Visa's proposal was "fair and reasonable" and that it would recommend its shareholders take up the all-cash offer.
Earthport's shares have fallen more than 28% this year amid growing losses and expenses, forcing the firm to say last month that "fundamental" change was required in its strategy.
Earthport says it offers a lower-cost alternative to traditional payments systems by allowing banks and money transfer firms to have a single relationship instead of multiple ties with various payments channels around the world.
For Visa, cross-border payments, or transactions that involve parties in two or more countries, represents a growing business.
The volume of such payments rose 10% in the 2018 fiscal year, Visa said in October.
Earthport, which counts Bank of America Merrill Lynch and Japan Post Bank among its clients, said Visa's offer was a revised proposal that followed an indicative offer from the US company last month.