Market's Tuesday Effect - Due to Auto Investments?

It seems that many on-line brokers offer free automatic investments if they are made on Tuesdays only. Could this be the reason for the 'Tuesday Effect' that has seen positive Dow Jones movements for the last 20 Tuesdays in a row?

In comparison, if you remove all Tuesday trading from these 20 weeks, the market is only up 0.2% for this time period. Warning: ZH Ahead

In addition, for 2011:

quote:

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" [the] average move in the Russell on Tuesdays this year has been 43bps. This is a huge move, corresponding to 22% annualized return.

4 out of the 11 times the Russell moved more than 4% in a day were on Tuesdays, including the two best days in the Russell (8/9 up 6.9% and 10/4 up 6.4%).

Conversely, there were no Tuesdays when the Russell was down 4% or more (out of 7 such days)."

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I know, ZH, but anyway.

For the "no such thing as coincidence" crowd, this free Tuesday auto investment seems to attract the eye. Thoughts?