Stillwater Mining Company (NYSE:SWC) (TSX:SWC.U) (“Stillwater” or the “Company”) today announced that it has filed definitive proxy materials with the Securities and Exchange Commission (SEC) in connection with the Company’s 2013 Annual Shareholders Meeting, which will be held on May 2, 2013. The Board of Directors of Stillwater has also issued a letter to its shareholders urging them to vote for Stillwater’s highly-qualified slate of director nominees who have positioned the Company for meaningful platinum group metals (PGM)-focused growth at a time when PGM market dynamics are increasingly robust. All shareholders of record as of March 6, 2013 are entitled to vote at the 2013 Annual Shareholders Meeting. Stillwater encourages all shareholders to carefully review its definitive proxy filing and other materials and vote only their WHITE proxy card. For more information about Stillwater’s 2013 Annual Shareholders Meeting, please visit www.supportstillwater.com. The full text of the letter follows: March 20, 2013 Dear Fellow Shareholder: YOUR VOTE IS IMPORTANT – PLEASE VOTE THE WHITE PROXY CARD TODAY Under the leadership of our current Board and through the execution of a multi-year plan, Stillwater has positioned itself for meaningful platinum group metals (PGM)-focused growth at a time when PGM market dynamics are increasingly robust. Today, Stillwater is in a position to deliver increased shareholder value as many of our industry peers face significant operational and financial challenges. As such, we are pleased to inform you that the Company has nominated all of Stillwater’s qualified directors for reelection at the annual meeting. Given the Company’s strong position and positive momentum, it is disappointing that a hedge fund, the Clinton Group, is waging a battle for control of your Company even though it only recently acquired just 1.2% of our outstanding shares and has no relevant experience investing in mining companies. In fact, according to public filings, the Clinton Group has only invested in 18 mining companies, none of them PGM-focused, with an average holding period of only 1.2 quarters, suggesting a significant short-term bias. At Stillwater, the Clinton Group has leveled a number of misguided criticisms and self-serving demands against the Company which either (a) offer no new strategies that the Board is not already pursuing, or (b) are misinformed and/or misdirected and will, in our view, be value-destructive for Stillwater’s shareholders. Your vote is critical and we need your support at our upcoming Annual Meeting scheduled for May 2, 2013. Do not cede control of your Company to a dissident hedge fund with a misguided, value-destructive agenda. We urge you to vote your WHITE proxy card FOR your Company’s nominees TODAY by telephone, Internet, or by signing, dating, and returning the WHITE proxy card in the postage-paid envelope provided with our recently mailed Annual Meeting materials. YOUR BOARD HAS POSITIONED STILLWATER TO DELIVER INCREASED VALUE TO ALL SHAREHOLDERS Stillwater is the premier North American PGM producer. The Company has taken decisive actions over the past five years to become an industry leading low-cost PGM producer, both in terms of current annual PGM production, as well as PGM-focused growth initiatives going forward. Stillwater is particularly well-positioned to deliver significant value for shareholders in light of structurally embedded global supply constraints and growing worldwide demand for PGMs – especially palladium.