May was an off month for hiring by small companies, according to the latest CBIZ Small Business Employment Index.

The index, which is compiled by Independence-based business services firm CBIZ Inc. (NYSE: CBZ), fell by a seasonally adjusted 0.21% last month after a nearly 3.6% increase in April, the company said in a news release on Friday, June 4. CBIZ’s index tracks payroll and hiring trends for more than 3,500 companies nationwide that each have 300 or fewer employees.

“Small businesses may now be scaling back their hiring efforts after increasing headcounts for three consecutive months, beginning in February,” said Philip Noftsinger, an executive vice president at CBIZ who oversees the index, in a statement.