Editor's Note: Any reference to TheStreet Ratings and its underlying recommendation does not reflect the opinion of TheStreet, Inc. or any of its contributors including Jim Cramer or Stephanie Link. All three major indices are trading down today with the Dow Jones Industrial Average ( ^DJI) trading down 57 points (-0.4%) at 15,601 as of Monday, Aug. 5, 2013, 12:50 PM ET. The NYSE advances/declines ratio sits at 1,233 issues advancing vs. 1,686 declining with 120 unchanged. The Basic Materials sector currently is unchanged today versus the S&P 500, which is down 0.2%. On the negative front, top decliners within the sector include Petroleo Brasileiro SA Petrobras ( PBR), down 1.7%, Imperial Oil ( IMO), down 1.3%, Phillips 66 ( PSX), down 1.3%, Exxon Mobil Corporation ( XOM), down 0.9% and Statoil ASA ( STO), down 0.8%. Top gainers within the sector include Teck Resources ( TCK), up 1.9%, Williams Partners ( WPZ), up 1.9% and Dow Chemical ( DOW), up 0.8%. TheStreet would like to highlight 5 stocks pushing the sector lower today: 5. PetroChina ( PTR) is one of the companies pushing the Basic Materials sector lower today. As of noon trading, PetroChina is down $1.08 (-0.9%) to $116.79 on light volume. Thus far, 46,486 shares of PetroChina exchanged hands as compared to its average daily volume of 157,900 shares. The stock has ranged in price between $116.70-$117.48 after having opened the day at $117.06 as compared to the previous trading day's close of $117.87. PetroChina Company Limited produces and sells oil and gas in the People's Republic of China. The company operates in four segments: Exploration and Production, Refining and Chemicals, Marketing, and Natural Gas and Pipeline. PetroChina has a market cap of $218.0 billion and is part of the energy industry. Shares are down 18.0% year to date as of the close of trading on Friday. Currently there are 3 analysts that rate PetroChina a buy, 1 analyst rates it a sell, and none rate it a hold. TheStreet Ratings rates PetroChina as a buy. The company's strengths can be seen in multiple areas, such as its revenue growth and attractive valuation levels. We feel these strengths outweigh the fact that the company has had somewhat disappointing return on equity. Get the full PetroChina Ratings Report now. STOCKS TO BUY: TheStreet Quant Ratings has identified a handful of stocks that can potentially TRIPLE in the next 12-months. Learn more.