The Correlation of WTI crude oil and S&P500 index is at 26 years high. In Jan 2016 the correlation between S&P500 and WTI index is at 0.89, higher than any calendar month since 1990.
Historically oil and stocks are higher correlated during recession. During 2008 financial crisis correlation spiked above 0.80.
Investors are too much concerned about cheap oil as falling oil prices signal weakness in demand which foretells economic slowdown.
The countries like Russia and Brazil are mostly affected due to weak oil prices. These countries economy rely on oil exports. So chance of EM debt crisis can happen due to slump in oil prices.
So stock market prices is mostly dependent on oil price movement this quarter .Technically US Oil (WTI) is facing strong resistance around $33 and any break above $33 will take the crude till $35.89 (55 day ) .If US oil (WTI) breaks above $33 then chance of S&P500 to trade higher is more and it can reach till 1980 level.