Global outplacement firm Challenger, Gray and Christmas says planned layoffs surged in April.

The firm's monthly survey of businesses found that employers announced more than 40,000 job cuts, 17 percent more than in March. And it's up six percent from April a year ago.

John Challenger, CEO of the outplacement company, blames an increase in mergers and acquisitions.

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He notes that "companies don't need two corporate headquarters" when they combine resources.

But he says the resulting layoffs are "the good kind," which are seen "when the economy is in better shape" and companies are in a position to move ahead with restructuring and expanding.

But Challenger also notes that "doesn't mean for the people who lose their jobs after an acquisition that it's any easier."

The retail sector was the layoffs leader last month, with nearly 7,000. Challenger calls that "surprising." He says the cuts normally come in January and February after the holiday shopping season.

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