Capital One announced Thursday an agreement to acquire payments and spend management startup Brex for $5.15 billion, marking the latest major strategic acquisition under founder-CEO Richard Fairbank. The deal, structured as half cash and half stock, was disclosed alongside the bank's fourth-quarter earnings.

The acquisition follows Capital One's landmark $35 billion purchase of Discover Financial last year, which granted it control of a major payment network. Fairbank positioned the Brex deal as a key accelerant for the bank's ambitions in the business payments sector. "Acquiring Brex accelerates this journey," Fairbank stated, praising the fintech firm for building "a vertically integrated platform from the bottom of the tech stack to the top."

Brex, initially known for providing corporate cards and financing to venture-backed startups, has expanded its clientele to include larger established companies like Robinhood and Zoom. The acquisition price represents a significant discount from Brex's last private valuation of $12.3 billion in 2023, highlighting the broader valuation pressures facing the fintech sector.

According to a source familiar with the strategy, Capital One determined that Brex's integrated model—combining corporate cards, banking, and spend management software—represented the winning formula for the future of business payments. Brex co-CEO Pedro Franceschi acknowledged the benefits of scale, noting in an interview that combining with Capital One's resources would fuel growth faster than remaining independent, despite asserting that Brex was not compelled to sell.

Investors reacted cautiously, with Capital One's shares falling approximately 3% following the announcement.