Stock buy
I have seen several large transactions over the last several months or so.
Some for 500,000 shares some for 1,000,000 both on the buy and sell side.
This is not all that uncommon.
Here is one example from last year.
Arnold Van Den Berg initiated holdings in Trucking company YRC Worldwide, Inc.. His purchase prices were between $37.31 and $44.62, with an estimated average price of $39.9. The impact to his portfolio due to this purchase was 2.36%. His holdings were 2,763,067 shares as of 06/30/2007.