Thus far write-downs in excess of $10 billion (USD) has been the playground of HSBC. Predictions, if they are correct, show HSBC will have some company in that lofty arena. Shares of Merrill Lynch & Co. fell almost 8% Friday in their biggest one-day decline since the aftermath of the Sept. 11, 2001 terrorist attacks, after Deutsche Bank downgraded its stock and predicted the Wall Street giant might have to write down as much as $10 billion in relation to the subprime mortgage crisis.