Warren Buffett Goes Up Against Delta Air Short Sellers

• Team Buffett's new stake in airline stocks surprised many.
• Short sellers have been betting against airline stocks recently.
• One airline has seen a particularly sharp rise in short interest.

News that Berkshire Hathaway Inc. has bought into the airline stocks came as a surprise to many investors and Warren Buffett watchers, given Buffett's well-known aversion to the industry. Perhaps it came as a surprise to short sellers as well, who increased bets against several of these stocks between the October 14 and October 31 settlement dates. That is especially true for Delta Air Lines, Inc. (NYSE: DAL).

Oh, Delta

This Atlanta-based air transportation giant saw the number of its shares short jump around 34 percent to more than 12.17 million in the final two weeks of the month. That was 1.6 percent of the total float, and the move ended three-straight periods of falling short interest in the stock. At the most recently average daily volume, it would take more than a day to cover all short positions.

Back in mid-October, Delta offered an earnings beat for the third quarter. The share price ended the two-week short interest period more than 4 percent higher, while the S&P 500 was down fractionally. In the past week, shares are up more than 7 percent, yet they are still more than 5 percent lower year-to-date.