"It seems that the major catalyst for this selling is the fact that the newest large banks primarily J. P. Morgan, Goldman Sachs, and possibly Morgan Stanley as well ? have issued massive margin calls to hedge funds and other professional traders who use these banks as prime brokers. These calls were not issued because of market losses, but more because the banks arbitrarily decided that they wanted their customers to use less leverage. Margin rates as low as 15% for broker dealers were raised to 35%; hedge funds who had been used to operating on high leverage were told that they had to bring accounts up to a much larger percentage of equity. In this illiquid environment, where all manor of exotic securities literally have no bids, the only place to raise the cash to meet margin calls was to sell stock. That is what really set this market over the edge ? as the first notice of these calls were issued on October 2nd and 3rd. There was something of a grace period to meet the calls, but funds realized they weren?t going to be able to meet them other than by selling stock. There are rumors that the most massive of the calls are due Monday (October 13th). If so, this market could continue to decline through then.
There doesn?t seem to be any reason for this increase in margin. The most benign one is that the banks became overly worried that their prime brokerage customers could cause problems with leverage. A more sinister reason revolves around the fact that the banks issuing the calls will likely wind up the owners of some excellent inventory (relatively illiquid preferreds, bonds, etc., which are being sold at prices well below theoretical value). They are in effect confiscating from their prime brokerage customers.