"Companies appear to be preparing for a contraction in the market," says Challenger, Gray & Christmas.
The last time so many U.S. chief executives left their posts, the country was sliding into a historic recession.
The May total of job cuts was 27% lower than it was for the same month a year ago.
But March headcount reductions were still nearly 32% higher than one year ago.
Employers reported 75,114 planned layoffs in January, up 218% on December and 42% on the year-ago period.
While layoffs for the year are on pace to be the highest since 2009, that is due to a "handful of industries" including oil.
April layoff numbers were the highest since May 2012, reports Challenger, Gray & Christmas.
