Brokerage and investment bank Merrill Lynch & Co. is expected to post a loss for its fiscal third quarter, battered by problems in the credit market.

Merrill (NYSE:MER) - which has already said it will take a $5 billion charge related to loans to people with poor credit and losses in complex credit instruments known as collateralized debt obligations – is expected to post a loss of 45 cents per share on sales of $3.25 billion, according to a poll of analysts by Thomson financial.

Merrill anticipates the loss could be as great as 50 cents per share.

At the start of October, all three major credit rating agencies dropped Merrill's credit rating from stable to negative as a result of the company's losses.

Fitch Ratings said it anticipates that during the next 12 to 18 months, liquidity and pricing challenges will prevail, lowering sales, causing investment write-downs and fewer trading opportunities.