Business leaders expressed increased optimism about the nation’s economy, though they still have a significant level of concern about the future, according to a quarterly survey by Chicago-based Grant Thornton LLP.

A November survey of 362 senior executives nationwide found 47 percent believe the economy will improve over the next six months, up from 34 percent in the August survey. And 43 percent plan to increase staff, compared with 38 percent in August.

Still, 52 percent remain concerned about the possibility of a double-dip recession.

While the overall business optimism index rose from the August survey, it was down from the May result.