Amazon is transitioning its small business credit card portfolio to U.S. Bank and Mastercard. This move ends the company's long-standing partnership with American Express.

The new Prime Business Card and Amazon Business Card will launch this spring. U.S. Bank will issue the cards using the Mastercard network.

The partnership represents a major win for U.S. Bancorp. The institution currently serves more than 1.4 million small business clients.

The new cards offer rewards for all purchases and feature no annual fees. They also provide flexible credit terms to help businesses manage cash flow.

Current Amazon Business American Express cardholders can continue using their accounts. Amazon will provide transition details to existing users soon.