Editor's Note: TheStreet ratings do not represent the views of TheStreet's staff or its contributors. Ratings are established by computer based on metrics for performance (which includes growth, stock performance, efficiency and valuation) and risk (volatility and solvency). Companies with poor cash flow or high debt levels tend to earn lower ratings in our model All three major indices are trading up today with the Dow Jones Industrial Average ( ^DJI) trading up 97 points (0.7%) at 14,670 as of Tuesday, April 2, 2013, 12:49 PM ET. The NYSE advances/declines ratio sits at 1,756 issues advancing vs. 1,114 declining with 151 unchanged. The Basic Materials sector currently sits down 0.7% versus the S&P 500, which is up 0.6%. On the negative front, top decliners within the sector include Eldorado Gold ( EGO), down 6.4%, Valero Energy Corporation ( VLO), down 4.6%, Silver Wheaton Corporation ( SLW), down 4.2%, Kinross Gold Corporation ( KGC), down 3.9% and ArcelorMittal ( MT), down 3.4%. Top gainers within the sector include Eni SpA ( E), up 2.2%, Cameron International Corporation ( CAM), up 2.1%, Tenaris ( TS), up 1.4%, Schlumberger ( SLB), up 1.4% and PetroChina ( PTR), up 1.2%. TheStreet Ratings group would like to highlight 5 stocks pushing the sector lower today: 5. Tesoro Corporation ( TSO) is one of the companies pushing the Basic Materials sector lower today. As of noon trading, Tesoro Corporation is down $1.89 (-3.3%) to $54.96 on average volume Thus far, 2.2 million shares of Tesoro Corporation exchanged hands as compared to its average daily volume of 3.6 million shares. The stock has ranged in price between $54.73-$57.14 after having opened the day at $57.10 as compared to the previous trading day's close of $56.85. Tesoro Corporation, together with its subsidiaries, engages in refining and marketing petroleum products in the United States. It operates in two segments, Refining and Retail. Tesoro Corporation has a market cap of $8.0 billion and is part of the energy industry. The company has a P/E ratio of 11.2, below the S&P 500 P/E ratio of 17.7. Shares are up 29.1% year to date as of the close of trading on Monday. Currently there are 9 analysts that rate Tesoro Corporation a buy, no analysts rate it a sell, and 4 rate it a hold. TheStreet Ratings rates Tesoro Corporation as a buy. The company's strengths can be seen in multiple areas, such as its revenue growth, solid stock price performance, impressive record of earnings per share growth, compelling growth in net income and reasonable valuation levels. We feel these strengths outweigh the fact that the company shows low profit margins. Get the full Tesoro Corporation Ratings Report now. Exclusive Offer: Jim Cramer's 'go-to' small/mid-cap guru Bryan Ashenberg only buys stocks he thinks could return 50-100%. See his top picks for 14-days FREE.