UAL Corp. (UAUA) is down 50 cents to $3.76. 26,000 UAUA calls have traded on the day, which represents about 5X (478 percent) the expected for this time of day. June 5 calls are the most actives, looks like buyers taking new positions. 15.3K traded, open interest of 1,483 and 96 percent trading ask-side. Implied volatity rallying to 217, up from 190 yesterday and highest levels since Nov. 21.