NEW YORK ( TheStreet) -- United Continental Holdings Inc (NYSE: UAL) is trading at unusually high volume Wednesday with 22.7 million shares changing hands. It is currently at four times its average daily volume and trading down $1.61 (-6.6%) at $22.83 as of 3:37 p.m. ET. United Continental has a market cap of $8.5 billion and is part of the services sector and transportation industry. Shares are up 2.6% year to date as of the close of trading on Tuesday. United Continental Holdings, Inc., through its subsidiaries, engages in the air transportation of persons, property, and mail. The company has a P/E ratio of 24.9, below the average transportation industry P/E ratio of 25.4 and above the S&P 500 P/E ratio of 23.2. TheStreet Ratings rates United Continental as hold. The company's strengths can be seen in multiple areas, such as its robust revenue growth, solid stock price performance and impressive record of earnings per share growth. However, as a counter to these strengths, we also find weaknesses including unimpressive growth in net income and poor profit margins. You can view the full United Continental Ratings Report. See all heavy volume stocks in our stocks moving on unusual volume list or get investment ideas from our investment research center.