Microsoft’s (MSFT) decision to keep Office away from iPad may be a good way to protect sales of Windows tablets but it’s also costing the company a pretty penny in terms of potential revenues. AppleInsider has picked up on some recent research from Morgan Stanley analyst Adam Holt showing that Microsoft is leaving $2.5 billion on the table every year by not bringing Office to Apple’s (AAPL) popular tablet. Some internal Microsoft documents leaked late last year suggested that Microsoft was finally developing a mobile version of Office for both iOS and Android, although the company has yet to make any announcements yet about bringing its popular productivity apps to rival mobile operating systems. There’s some added urgency for Microsoft to make its Office suite available on more mobile platforms since Google (GOOG) has recently started moving into its enterprise territory with its Google Apps productivity software.

Prior to joining BGR as News Editor, Brad Reed spent five years covering the wireless industry for Network World. His first smartphone was a BlackBerry but he has since become a loyal Android user.