Ms. Piepszak, chief executive of Chase Business Banking, was armed with an internal corporate strategy report outlining the opportunity the company had to better cross-sell small business banking, credit card and payment processing services that could lead to hundreds of millions of dollars in additional revenues. An estimated 43% of small businesses with more than $100,000 in annual revenues use all three products: checking, credit cards and merchant acquiring, according to a small business survey by consultancy Oliver Wyman. But J.P. Morgan, which serves 3.9 million American small businesses, found less than 10% of its customers use Chase for all...