Who Traded 55,000 Bear $30 Puts Tuesday?

This past Tuesday, when Bear Stearns was trading around $65 a share, there was huge put volume in the March $30 strike.
Over 55,000 contracts traded that day at an average price of 15 cents a contract. This is an extremely unusual trade in terms of the number of contracts and how far out-of-the money those options were at the time; these options expire on March 20, so that left only 10 days for some event to occur that would cause these puts to go into the money and have some value.
So it appears that as rumors began swirling early in the week that Bear was having liquidity problems and might possibly be bordering on insolvent, someone took that to heart and bought the puts as disaster insurance. And today came news that several banks, including Goldman Sachs, would no longer act as a counterparty to any transactions with Bear. The inability to execute trades would essentially put Bear Stearns out of business.
Hence, we have today's selloff in which shares of Bear are down some $25, or 44% to around $30 a share. Those disaster put options are trading around $5.50 a contract.
Other banks and brokerage firms are seeing put volume today and several names such as Merrill Lynch saw above average activity last week. Merrill saw 13,000 and 16,000 of the March $45 puts traded last Thursday and Friday, respectively. That volume was over 13 times the 30-day daily average. At the time the stock was trading around $46 and the puts were valued at about $1.50 a contract. Today Merrill is down to $44 and the puts are worth $2.60 a contract.