NEW YORK--(BUSINESS WIRE)--U.S. middle market companies have a rosy outlook on both their business prospects and the economy, according to the American Express Survey of Mid-sized Companies, which interviewed companies with revenues of $10 million to $1 billion annually. Nearly three-quarters of financial decision makers (73%) in the U.S. middle market expect the economy to grow over the next twelve months and a similar number (75%) expect the economy will have a positive impact on their compan