A lack of qualified candidates, economic conditions and competition were all cited for their more conservative outlook.

Other key findings:

• 72 percent of respondents said they generate 50 percent or more of their revenue from repeat client business.
• 22 percent of respondents reported that 50 percent or more of their revenue comes from their largest client.
• 71 percent of respondents admitted to having a shortage of skilled candidates in their respective sectors for 2014 vs. 76 percent for 2013.

"(Last year) was by almost all accounts a very good year for the staffing and recruiting industry," Bullhorn said in its report. "Overall revenue, as well as total number of placements — the most important metric for firms across the board — increased over the past year. However, there are signs of a slowdown for 2014. Agencies are more conservative about their growth plans, and some firms are overly reliant on a single large client for revenue."

That conservative approach can also be seen in hiring plans for 2014. Seventy-five percent of respondents said they plan to grow their head counts this year. However, this is less aggressive than last year, when 82 percent planned to add staff, Bullhorn said.

"Interestingly, (agencies) that consider recruiting technology important are more than twice as likely to open new branch locations in 2014," the firm noted.

Twenty-six percent of those firms plan to expand branch locations in 2014. For those who are neutral or consider recruiting technology unimportant, only 12 percent plan to expand branch locations, it said.

On the question of relying on too few clients, 48 percent of upper-midsize respondents said they get 70 percent or more of their revenue from their largest client.

Bullhorn also asked respondents if they could stay in business if they lost their largest client. Only 6 percent of respondents admitted they'd close if this were the case, despite the large number that reported relying on so much of their revenue from just one large client.