CHICAGO--(BUSINESS WIRE)--The strength and consistency of U.S. Bancorp's (USB) earnings performance continues to support the company's high ratings (Viability Rating of 'aa-'), according to Fitch Ratings. The second quarter of 2015 (2Q15) continued this trend with the company delivering a return on average assets (ROA) of 1.46% and a return on average equity (ROE) of 14.3% in 2Q15. In Fitch's view, the strength of USB's results is due to a dual cost advantage relative to peer institutions. Firs