10 things you need to know before the opening bell

Here is what you need to know.

Stock markets around the world are sharply lower. Japan's Nikkei (-3.8%) led the way lower in Asia and Germany's DAX (-2.3%) paces the decline in Europe. S&P 500 futures are down 39.00 points at 1930.25.

Chinese manufacturing data was weak. China's Manufacturing PMI fell to 49.7 in August, making for the first contraction in the sector since February. Business Insider Australia says, the internals of the report were weak with new orders and new export orders both slowing. Elsewhere, the Caixin Final Manufacturing PMI reading sank to 47.3, posting its worst reading since March 2009. The yuan strengthened 0.2% to 6.3642 per dollar.

Macau gaming revenue crashed. Gaming revenue in Macau crashed 35.5% in August, marking a 15th straight monthly decline, according to the FT. The pronounced slowdown comes after Beijing's crackdown on VIP gaming, but weakness can also be seen in the "mass" revenue data. Yesterday, Macau announced second quarter GDP collapsed 26% compared to last year.

South Korean exports plunged. Exports tumbled 14.7% in August, compared to a year ago, much worse than the 5.9% drop economists were forecasting. This is troubling fas the country's exports are commonly referred to as the global economy's "canary in the coal mine." Exports to Japan (-20.9%), Latin America (-19.3%), Europe (-7.7%) and China (-7.6%) saw big declines. Notably, exports to the US rose 3.4%. The South Korean won climbed 1% to 1171.70 per dollar.

Euro zone unemployment fell to levels last seen in 2012. Euro zone unemployment fell to 10.9% in July, hitting its lowest level since 2012. German unemployment was the lowest in the region, dipping to 4.7%. There was more good news on the jobs front as euro zone youth unemployment fell to 21.9%, the tamest since October 2011.

French Manufacturing continues to reel. France's Final Manufacturing PMI fell to 48.3 in August, from 48.6 in July. The number was shy of the 48.6 that economists were forecasting and makes for the worst reading in four months. Italy and Spain also saw slowdowns in manufacturing while Germany's reading climbed to 53.3, its best level since May 2014. The euro zone as a whole saw its reading slip to 52.3 from 52.4. The euro is stronger by 0.5% at 1.1267.

Puerto Rico won an extension. Puerto Rico Aqueduct and Sewer Authority's (PRASA) $90 million credit facility payment has been pushed back until at least September 15 to give authorities more time to orchestrate a $750 million bond sale, according to Reuters. Alberto Lazaro, executive president of PRASA, says authorities are waiting for better market conditions to price the offering.

Crude oil saw its biggest 3-day rally in 25 years. On Monday, crude oil gained 8.8% to finish at $49.20 per barrel. The gain capped off a 27%, rally, which was the largest three-day advance since 1990, when Iraq invaded Kuwait, according to Bloomberg. Currently, crude oil is down 1.9% at $48.25 per barrel.

Greenlight Capital had a bad August. Hedge fund manager David Einhorn's Greenlight Capital lost 5.3% in August, people familiar with the matter told the Wall Street Journal. The poor August has Greenlight Capital down 13.8% in 2015, and on track for its first losing year since 2008. According to the WSJ, 2008 was Greenlight's only losing year since it was founded in 1996. In a letter to its investors, Greenlight said the losses "came primarily" from its holdings of Consol Energy, Micron Technology and Sun Edison.

US economic data is moderate. ISM Index and construction spending are due out at 10 a.m. ET while auto and truck sales cross the wires throughout the day. The US 10-year yield is lower by 6 basis points at 2.16%.