BBVA last week announced a new round of investing in Atom, a U.K.-based mobile-only bank. The investment will enable BBVA to continue as the main strategic investor in Atom, maintaining a stake of around 29.5 percent, according to a press release.

BBVA added 34.1 million euros ($36 million) to Atom's capital increase, according to the announcement.

"Atom has a lot of promise, with tremendous opportunities for growth," Javier Rodríguez Soler, global head of strategy and mergers and acquisitions at BBVA, said in a statement. "It allows BBVA to further its transformation and maintain its commitment to the British market."

Atom launched in April with two fixed saver accounts and a loan offering for SMEs. The bank recently launched its first mobile mortgage product, and plans to launch additional products this year.

"We will keep growing, rolling out new products and developments of our app and offering a whole new way of banking on our mission to change banking permanently for the better," Atom Founder and Chairman Anthony Thomson said in a statement. "The activity in the U.K. market will continue to gather heat in 2017 and we are confident we have a firm foundation to keep making headway."