MBD revenue decreased, mainly reflecting $189 million of revenue deferred primarily related to the Office Deferral, offset in part by overall increased sales of the 2010 Microsoft Office system. Business revenue increased $142 million or 3%, primarily reflecting growth in multi-year volume licensing revenue and a 6% increase in Microsoft Dynamics revenue. Consumer revenue decreased $275 million or 25% driven by the Office Deferral and a decline in the PC market.
MBD revenue for the three months ended September 30, 2012 included an unfavorable foreign currency impact of $119 million.
MBD operating income decreased, mainly due to lower revenue, offset in part by decreased research and development expenses. Research and development expenses decreased $64 million or 13%, primarily due to the capitalization of certain Microsoft Office system software development costs, offset in part by increased headcount-related expenses.