BBVA has acquired San Francisco user-experience firm Spring Studio, in a bid to improve the look and feel of its digital banking services.

Spring Studio, which began in 2001 and has 38 employees, has helped design digital products and services for Fortune 500 brands and startups. Co-founders Bruce Randall and Sanjay Shamdasani announced the firm's new owner in a blog post Wednesday.

"BBVA is on a mission to be the world's No. 1 digital bank," Randall and Shamdasani wrote. "They recognize that as the bank becomes more digital, exceptional design is not optional. It has to be at the heart of what they do and needs to be part of the organization's DNA."

BBVA said Spring Studio will continue to work independently but will focus on BBVA projects in the U.S. and South America.

The acquisition follows Capital One's purchase of digital design firm Adaptive Path in the fall. The investments by the banks point to the growing importance of designing easy-to-use digital experiences as more consumers bank through digital devices.

Design is "fundamental to the success of the business," BBVA said in a press release.

BBVA, which stands for Banco Bilbao Vizcaya Argentaria, in Bilbao, Spain, has been recognized for its aggressive M&A pursuits in the digital arena. It acquired neobank Simple and big-data startup Madiva Soluciones in 2014.

Its U.S. unit, BBVA Compass Bancshares, has 672 branches in seven states including Alabama, Texas and Arizona.