CHARLOTTE, N.C. – More than 53 percent of businesses participating in a new Grant Thornton survey plan to increase hiring over the next six months.

In a new Grant Thornton Business Optimism Index report, the accounting and financial services firm reported a mixed bag of results.

While the percentage of firms planning to increase headcount is the highest since June of 2005, only 30 percent of business leaders expect the economy to improve.

That’s the same total since June of last year.

Overall, executives remain optimistic about the future of their own businesses, with 84 percent being optimistic about growth. That’s down from 87 percent from June.

“Although business leaders are less optimistic about the economy as a whole, it is promising that they continue to remain optimistic about the opportunities for their own companies,” said Mike McGuire, Carolinas Managing Partner for Grant Thornton. “These findings suggest that mid-cap, small-cap and private companies are confident that they can handle the current economic challenges, and are poised to explore growth opportunities.”

The overall Grant Thornton Business Optimism Index increased to 64.1, up from 62.8 last June.

Harris Interactive conducted telephone interviews in November and December for Grant Thornton. Some 302 senior executives at firms with revenues between $50 million and $2 billion participated.

By categories, executives reported:

• 30 percent believe the U.S. economy will improve

• 15 percent believe the economy will worsen

• 84 percent are optimistic about their own business

• 53 percent plan to add staff

The index is based on executives’ views about the economy, business growth and hiring expectations.