September was a brutal month for job cuts

The third quarter has ended with an eye-opening round of job cuts across the U.S. corporate sector, with signs that trend will continue into the last months of 2015.

Food giant ConAgra (CAG), maker of Chef Boyardee, Slim Jim, Reddi-Wip, Hebrew National hot dogs and a variety of other products, on Thursday announced it would cut around 1,500 jobs, or about one-third of its overall office-based workforce. The company, which reported a first-quarter loss of $1.2 billion last month, is also moving its headquarters from Omaha, Nebraska to Chicago.

Several weeks ago Hewlett-Packard (HPQ), the struggling computer firm, said it plans to shed 30,000 positions. There are also reports that Walmart (WMT) will begin cutting hundreds of jobs starting next week.

According to the outplacement consultancy firm Challenger, Gray & Christmas, September was an especially brutal month for pink slips, with U.S.-based employers eliminating nearly 59,000 jobs last month. That's up 43 percent from August and 93 percent higher than in the year-ago period. The total number of layoffs between July and September was 75 percent higher than in the third quarter of 2014.

John Challenger, CEO of Challenger, Gray & Christmas, said job cuts in 2015 have already topped last year's figure and are on pace to end the year at their highest level since 2009, when 1.3 million workers were laid off as the Great Recession was coming to a close.

While the computer industry was hit hard, the largest sector to experience employee reductions was energy, with close to 73,000 jobs cut since January.

Challenger Gray says tumbling prices on the global oil market, as well as the ongoing economic slowdown in China, the world's second-largest economy, are having a ripple effect beyond energy into construction and other related industries.

"We could see more fallout, which appears to have its origins in China, which after years of building up its national infrastructure appears to now have far too much capacity," Challenger said in a statement.

Although the economic doldrums in the People's Republic are expected to have a continued impact on the U.S. economy, Challenger said the recovery remains on track.