NEW YORK ( TheStreet) -- Semgroup (NYSE: SEMG) is trading at unusually high volume Friday with 1.3 million shares changing hands. It is currently at four times its average daily volume and trading down 62 cents (-2%) at $29.56 as of 12:49 p.m. ET. Semgroup has a market cap of $1.3 billion and is part of the basic materials sector and energy industry. Shares are up 15.8% year to date as of the close of trading on Thursday. SemGroup Corporation, through its subsidiaries, engages in moving energy products from wellheads to the wholesale marketplace through a network of pipelines, terminals, and storage tanks in the United States, Canada, Mexico, and the United Kingdom. TheStreet Ratings rates Semgroup as a hold. The company's strengths can be seen in multiple areas, such as its impressive record of earnings per share growth, compelling growth in net income and largely solid financial position with reasonable debt levels by most measures. However, as a counter to these strengths, we find that the company's profit margins have been poor overall. You can view the full Semgroup Ratings Report. See all heavy volume stocks in our stocks moving on unusual volume list or get investment ideas from our investment research center.