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 up today with the Dow Jones Industrial Average ( ^DJI) trading up 44 points (0.3%) at 15,539 as of Tuesday, Sept. 17, 2013, 12:50 PM ET. The NYSE advances/declines ratio sits at 1,783 issues advancing vs. 1,120 declining with 134 unchanged. The Basic Materials sector currently sits up 0.1% versus the S&P 500, which is up 0.3%. On the negative front, top decliners within the sector include Potash Corporation of Saskatchewan ( POT), down 1.8%, Marathon Petroleum ( MPC), down 2.0%, Phillips 66 ( PSX), down 1.6%, Monsanto Company ( MON), down 0.9% and Air Products & Chemicals ( APD), down 0.9%. Top gainers within the sector include Whiting Petroleum Corporation ( WLL), up 3.9%, Consol Energy ( CNX), up 2.1%, LyondellBasell Industries ( LYB), up 1.6%, Apache Corporation ( APA), up 1.7% and Cabot Oil & Gas Corporation ( COG), up 1.4%. TheStreet would like to highlight 5 stocks pushing the sector lower today: 5. Western Gas Partners ( WES) is one of the companies pushing the Basic Materials sector lower today. As of noon trading, Western Gas Partners is down $1.71 (-3.0%) to $55.02 on heavy volume. Thus far, 203,915 shares of Western Gas Partners exchanged hands as compared to its average daily volume of 167,500 shares. The stock has ranged in price between $54.58-$57.26 after having opened the day at $56.51 as compared to the previous trading day's close of $56.73. Western Gas Partners, LP owns, operates, acquires, and develops midstream energy assets in east, west, and south Texas; the Rocky Mountains; and the Mid-Continent. Western Gas Partners has a market cap of $6.5 billion and is part of the energy industry. Shares are up 22.1% year to date as of the close of trading on Monday. Currently there are 7 analysts that rate Western Gas Partners a buy, no analysts rate it a sell, and 4 rate it a hold. TheStreet Ratings rates Western Gas Partners as a buy. The company's strengths can be seen in multiple areas, such as its revenue growth, increase in net income, expanding profit margins, solid stock price performance and growth in earnings per share. We feel these strengths outweigh the fact that the company has had somewhat disappointing return on equity. Get the full Western Gas Partners 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.