June 21 - Standard & Poor's Ratings Services said today that it assigned its 'BB+' senior unsecured debt rating to Western Gas Partners L.P.'s proposed $520 million senior unsecured 10-year bullet notes. The recovery rating on the notes is '3', indicating our expectation for meaningful recovery (50% to 70%) if a payment default occurs. Western Gas has also completed a concurrent equity offering of 5 million common units, earlier this week. The partnership will use proceeds from the unsecured note and common unit offerings to pay down roughly $334 million of the revolving credit facility borrowing and a $175 million issue of 2.82% notes due 2013 payable to parent Anadarko Petroleum Corp. It will use any additional net proceeds for general partnership purposes, the company stated. Adjusted debt leverage should range between 3.5x to 3.0x in 2012, and liquidity should remain strong pro forma for the issuance. RELATED CRITERIA AND RESEARCH Key Credit Factors: Criteria For Rating The Global Midstream Energy Industry, April 18, 2012 RATINGS LIST Western Gas Partners L.P. Corporate credit rating BB+/Positive New Rating $520 mil senior unsecured notes BB+ Recovery rating 3 Complete ratings information is available to subscribers of RatingsDirect on the Global Credit Portal at www.globalcreditportal.com. All ratings affected by this rating action can be found on Standard & Poor's public Web site at www.standardandpoors.com. Use the Ratings search box located in the left column.