For the first time in thirteen years, Nokia’s credit rating has been downgraded by Standard & Poor’s Rating Service. The Finnish phone maker, which has held an A rating since 1998, has been under the financial microscope in recent years due to the rise of its competitors and, more recently, for its software deal with Redmond-based Microsoft. “The downgrade reflects the revision of our business risk profile assessment on Nokia to ‘satisfactory’ from ‘strong,'” writes S&P in its report. “We expect that Nokia’s smartphone portfolio will make further significant market share losses during 2011 and 2012 until it has completed its adoption of Microsoft’s Windows Phone software as its new primary software platform for smartphones.” The company’s new credit rating is A-. Nokia’s smartphone market share fell 9-points last year, from 40% in Q4 of 2009 to 31% in Q4 of 2011. The company’s stock was trading down slightly on the news.