Capital One-Discover Deal Aims to Challenge Visa, Mastercard (2)

For decades, Capital One Financial Corp. Chief Executive Officer Richard Fairbank watched as Discover Financial Services built one of the most coveted assets in the world of finance—a global payment network facilitating tens of millions of credit card transactions each day. On Feb. 19 he announced plans to buy it.

The $35 billion deal—the biggest merger announced globally this year—would unite two storied consumer-finance brands and create the largest credit card issuer in the US by loan volume, surpassing the likes of American Express, Citigroup and JPMorgan Chase.

Opposition emerged almost immediately from Democrats in the US Senate, ...