Venus will be opposing Uranus and squaring Pluto over the weekend, and this effect may extend a bit into Mon, Sep 20. While it’s a quick passing influence, there may be some unexpected up-and-down swings in the market on Fr and during the after-hours trading.
In the past, I noticed that “hard” aspects between Venus and Uranus (i.e., conjunction, square, and opposition) often coincide with greater than average swings in FOREX trading (e.g., 100 or more pips). Therefore, I’d say on Fr there will likely be an increase in opportunities for day traders for quick profit here and there, catching swings in both directions.
Tolstunka 
On Sunday, Sep 19, 2011, a strong 6.8 earthquake hit northeastern India
http://news.yahoo.com/strong-earthquake-hits-northeastern-india-131314474.html
As mentioned in another post, the square bet. Uranus & Pluto is ongoing and will last a few more years. When transiting planets form hard aspects to the sensitive degrees of this powerful square (as Venus did on Sat-Sun), disruptive energy will be more likely to manifest through some unexpected events and trigger stock market moves.
SYDNEY, Sep 19, 2011, 9:35am: “Euro skids, seen heading to $1.3590… The euro, which had just clinched its best week in two months, was last at $1.3688, down from $1.3790 late in New York on Friday.” http://www.reuters.com/article/2011/09/18/markets-forex-idUSL3E7KG05220110918
Monday, Sep 19, 2011
3 earthquakes rock Guatemala: The largest quake, a 5.8 magnitude, hit at 12:34 p.m., with two of 4.8 magnitude hitting before and after. http://news.yahoo.com/3-earthquakes-rock-guatemala-1-confirmed-dead-202141923.html
DJI opened a little over 2% down from previous Fr close, then gained a bit in the afternoon, for the total of (-0.94%) for the day.
So, it seems that Venus triggering Uranus-Pluto square over the weekend did affect market opening on Mon morning, with a relatively large discrepancy bet. Fr-close & Mon-open due to after-hours trading.