That pretty much tells it all. That means, people who are long on EXPE are wanting to sell here and since shares are not available to sell, the broker is calling back short shares. I agree that from here, the stock will continue to trickle down and USAI will drop accordingly as well IMO.
Hunch, the primary reason that brokers do margin calls -isn't- because shares aren't available. That's kind of a nutty theory.
Rather, it is because the brokerage monitors the credit risk (i.e., an investor's ability to buy back stock), which is a function of the stock price and the individual's presently invested assets with the brokerage firm.
The invested assets in the firm generally need to be large enough to cover a substantial portion of the stock. If the stock rises rapidly, brokerages often ask for more money invested. Not a big deal.
"That means, people who are long on EXPE are wanting to sell here"
To jeff and other EXPE longs I am gonna make this one simple. If you now continue to hold your shares for "more" you would have to either crazy or a fool! I would be dumping as fast as I could at this point. This deal is dirty and only going to get worse. Nomad