San Diego's Bridgepoint Education, the for-profit university under Congressional attack as well as government investigation, is the most heavily shorted stock among 3,000 U.S. stocks, according to the publication Seeking Alpha. A whopping 58.79% of Bridgepoint's trading stock is short -- that is, investors are hoping the stock will go down. The shorts borrow shares, sell them, and expect to buy them back at a lower price. The next highest on the list has 51.75% of its float short. Generally, speculators often consider a high short position bullish. If something good happens to the company, the shorts may rush to cover (buy the stock) and send it upward. Bridgepoint stock is down 10% this year. Senator Tom Harkin regularly points out that 84% of the two-year students at its Ashford subsidiary drop out, and 63% of four-year students don't finish. But the company exists on federal government loans that account for 85% of its revenue -- and probably close to 100% if military recruits would be included. The company has startlingly high profits and an amazing $230 million in cash, but an investigation by the Department of Education could deprive it of federal support -- thus sinking the company. However, if DOE bows to Republican pressure and gives the company a wrist slap, the shorts could cover and the stock could roar upward.

Also on Seeking Alpha's list of 50 most shorted stocks is biotech Orexigen, which is trying to develop a diet pill. The stock has bounced up and down depending on the outlook for Food and Drug Administration approval. The short position for Orexigen is 26.33%. The stock is down 65% on the year. Orexigen lost 6.08% today to $3.09. Bridgepoint dropped 0.29% to $16.96.