To be able to predict the future one has to study the past.
During the 2000 Internet Bubble & 2007 Financial Crisis S&P 500 shed about 50% of it's Value (in both crisis).
And it fell to same support line which is between 800 (2000) and 700 level ( 2009 ).
FORECAST Feb. 2016 Forward
IF S&P 500 act is consistent in CRISIS MODE, we should expect it to shed close to 50% from the 2015 high (2100).
This should reach 1100 LEVEL...From crisis, the down trend continued for about 14 months.
IN BOTH PREVIOUS CRISIS IT TOOK ABOUT A YEAR+ TO THE BOTTOM.
AGAIN IF S&P 500 IS CONSISTENT IN IT'S' BEHAVIOR DURING CRISIS WE SHOULD SEE NEAR BOTTOM BY END OF 2016 EARLY 2017
What's the bottom?
It is hard to predict, but according to the above, it could be any of the support levels in the chart.
Best case scenario, is we bounce of 1500 Level and market recover.
Worst case scenario is we trend down and pass 1400 and 1300 support levels all the way to 1090 level.
Current global economic and political signals are not favorable, plus the over valuation of equities in US and China is adding a sell pressure that is felt across global markets.
Oil is a political game and can fluctuate or shoot up any given time, this will not make the market more volatile.
Please note the above is based on the assumption "IF SPX is consistent in its behavior in Crisis mode".