Futures are getting slammed

US stock futures are getting crushed.

On Tuesday night, we got the latest manufacturing data out of China, and it was ugly. Markit's Purchasing Manufacturer's Index (PMI) came in at 47.0 for September, the lowest level since March 2009.

Nearly every sub-component of the index, including employment, new orders, and output were decreasing at a faster rate.

US stocks closed lower on Tuesday, with the Dow dropping 179 points. And following a rebound in futures trading on Tuesday night, the indexes lost ground again, with the Dow shedding as many as 140 points.

Concerns about global growth have been front and center stage of markets, particularly after the sell off in August.

Last week, the Federal Reserve again delayed its first interest rate increase in nine years, this time saying that it is "monitoring developments abroad".

And now, we have more confirmation that it's real ugly out there.