NEW YORK ( TheStreet) -- ZIOPHARM Oncology (Nasdaq: ZIOP) is trading at unusually high volume Friday with 1.8 million shares changing hands. It is currently at 4.2 times its average daily volume and trading down 22 cents (-4.1%) at $5.10 as of 11:15 a.m. ET. ZIOPHARM Oncology has a market cap of $353.9 million and is part of the health care sector and drugs industry. Shares are up 20.6% year to date as of the close of trading on Thursday. ZIOPHARM Oncology, Inc., a biopharmaceutical company, focuses on the development and commercialization of in-licensed cancer drugs in North America. TheStreet Ratings rates ZIOPHARM Oncology as a sell. The company's weaknesses can be seen in multiple areas, such as its disappointing return on equity, weak operating cash flow, generally disappointing historical performance in the stock itself and feeble growth in its earnings per share. You can view the full ZIOPHARM Oncology Ratings Report. See all heavy volume stocks in our stocks moving on unusual volume list or get investment ideas from our investment research center. Interested in other stocks that are falling on unusually high volume? Get free SMS text alerts sent to you when the action happens by texting HVDOWN to 95370 or select from multiple alert options.