Chief executives' confidence in the economy rebounded in the first quarter, though they remain leery of taking on new workers at home, according to a survey released on Wednesday.

The Business Roundtable's CEO Economic Outlook Index rose to 81.0 in March, up from a reading of 65.6 in December, according to the quarterly survey, which was conducted before the recent sharp rise in the U.S. stock market.

The increase in confidence reflected improved expectations for sales and plans to boost U.S. capital spending over the next six months.

But CEOs remained unlikely to add workers, with just 29 percent planning to boost U.S. employment over the next six months, the same percentage as in December. The slow recovery in hiring has stood as one of the biggest drags on the United States' tepid recovery since the recession that ended almost four years ago.

Some 72 percent of CEOs expect their companies' sales to rise in the next six months, up from 58 percent who expected that in December, and 38 percent plan to boost U.S. capital spending, up from 30 percent in December.

The Roundtable surveyed 144 member CEOs from February 11 through March 1.

(Reporting by Scott Malone; Editing by Gerald E. McCormick)