Executives' third-quarter outlook for the U.S. economy is down, with more holding back on plans for capital spending in light of grimmer sales prospects. The latest reading of 79.1 in the Business Roundtable's CEO Economic Outlook Index is down from 84.3 in the second quarter as "business leaders still see headwinds preventing a more sustained, robust recovery," said Jim McNerney, chairman of the Business Roundtable and CEO of Boeing.