M&A Outlook Positive: Greenhill CEO

Merger-and-acquisition activity has been down in 2013 but shows signs of improvement, Greenhill CEO Scott Bok said Thursday.

"There's a lot of active dialogue going on," he said. "I think even in recent weeks you're seeing a few more deals, a few more rumors of deals."

On CNBC's "Fast Money," Bok noted that the number of billion-dollar transactions in the M&A space was down about 20 percent year to date.

"I think there really are two reasons for that," he said. "One is a longer-term one, which is that typically downturns were sort of two to three years in the M&A business. This time, we're really going on year six now, so I think it's just the financial crisis was a much deeper, more difficult event than past recessions, so it's taking long to recover.

"And the other thing is that I think the stock market has run up so much in recent months that I do think that's causing some buyers to pull back."

Last year's largest M&A deals included Berkshire Hathaway buying Heinz and Liberty Global buying Virgin Media.

Bok said that the dearth of headlines didn't mean deals weren't in the works.

"In weak periods like this, we try to just focus on getting close to clients, growing our market share, which we've done for a number of years now, and being ready for when the market does pick up," he said.