From here, we can reads that the next astrological dates of possible big shifts in the stock markets are:
17 February 2011, this seems to be a big one. No big aspects on the chart, but later by April, the Sun conjuncted with Saturn, while Mars joins Uranus in Aries, this seems to spell trouble, restriction or austerity, and some aggressiveness at the same time (riots? war?). I would say this time marks the early stages of a long-term down market trend!
29 July 2011, very likely at least market recession, Jupiter/Sun square. Also Mars (in revolutionary Gemini) is opposing Pluto and square Uranus. Time of BIG change. Likely time for a market crash, if not already underway.
28 December 2011, again likely a bad time for the economy, Jupiter-Saturn opposition, Sun-Uranus square and Sun-Pluto conjunction.
Minor shifts in 16 January (probably very dynamic, there is a Sun/Mars conjunction but sextile to Jupiter, probably positive, albeit this is only for short-term), 3 February and 16 June.
Very difficult to know, this is an experimental prediction, as usual. Let's see what happens