NEW YORK ( TheStreet) -- Shares of Sunoco (NYSE: SUN) were gapping up Monday morning with an open price 20.5% higher than Friday's closing price. The stock closed at $40.91 Friday and opened today's trading at $49.30. The average volume for Sunoco has been two million shares per day over the past 30 days. Sunoco has a market cap of $4.34 billion and is part of the basic materials sector and energy industry. Sunoco, Inc., through its subsidiaries, refines and markets petroleum products in the United States. Its Logistics segment operates refined product and crude oil pipelines and terminals; and acquires and markets crude oil and refined products. TheStreet Ratings rates Sunoco as a hold. Among the primary strengths of the company is its robust revenue growth -- not just in the most recent periods but in previous quarters as well. At the same time, however, we also find weaknesses including deteriorating net income, generally poor debt management and disappointing return on equity. You can view the full Sunoco Ratings Report. Get more investment ideas from our investment research center.