don’t know anything about large wm insiders, i just trade the stock, so I am not sure who the possible suspects are. AIG is a bit different, Greenberg came out and said he was going to sell a lot, starting immediately.
In WaMu's case, the FDIC set a Wednesday evening deadline for interested parties to submit their offers for various parts of WaMu. Twenty-four hours later, they were already preparing to seize the bank. Earlier this month, Treasury Secretary Henry Paulson made it clear to WaMu that the company should have accepted the takeover deal J.P. Morgan had offered earlier this year, according to a person close to WaMu.
The main players at JP Morgan knew full well on Wednesday evening that they were preparing to buy the plum assets of Wamu on Thursday evening after the close of the market, and so, if those players knew it, a significant number of other key Wall Street players knew it, too, including the WM NYSE floor specialist. The way trading went Thursday was carefully calibrated to suck in buyers for WM stock, buyers who were out of the loop of insider knowledge. The after-hours WM price plunge was a surprise only to the little retail investors who rarely have a clue (I'll include myself in that bunch).
That's my take, anyway...