it is very curious that the Bitcoin price didn't fall YET.

normally, any real "stock" market would have reacted until now. the "players" would have sold...I think Bitcoin foundation is not strange of this.

I bet this is Bitstamp themselves making some tricky maneuvers.

Here is the main cold wallet of Bitstamp: https://blockchain.info/address/1JoktQJhCzuCQkt3GnQ8Xddcq4mUgNyXEa

From the earliest transaction of the address: https://blockchain.info/tx/8f1d3a8ef6b2d4a25d2f499279e01518b4770819ccbc39a765c4c326170c61b3

the source addresses and destination address are all cold wallets of Bitstamp.  The total amount of these cold wallets are about 200K.

The 18k BTC lost is about 10% of total reserve of Bitstamp.