Microsoft is leaving billions of dollars on the table by not porting Office to the iPad, according to a new analyst report. That analyst, Morgan Stanley’s Adam Holt, believes that Office for iOS would sell to approximately 30 percent of all iPad users; priced at $60 per copy, that comes to a grand total of $2.5 billion per year—minus Apple’s cut of the revenues, of course. (Hat-tip to AllThingsD for picking up on Holt’s report.) Whether or not one agrees with Holt’s math, the underlying conceit makes sense: the world’s most profitable productivity software on the world’s most popular tablet would equal significant cash payouts for all involved. But while Microsoft hasn’t shut the door on the idea of Office for iOS, it’s not necessarily in the company’s best interest to rush such a platform to market, even if billions of dollars potentially hang in the balance—it’s too busy pushing Office as a cloud-based, OS-agnostic platform. That platform, Office 365 Home Premium, is available via the browser for a $99.99-per-year subscription fee. It’s a streaming version of Office 2013, the most recent update of Office that went on sale last month in 162 countries; even as it rolled out the “traditional” and cloud versions of Office, however, Microsoft took pains to highlight the latter as a better value. However, Office faces some significant competition in the cloud, most notably from Google Docs. In a January interview, Bloomberg asked Microsoft CEO Steve Ballmer about the prospect of Office on iOS. “I have nothing to say on that topic,” Ballmer said. “We have a product that we think makes a lot of sense. We do have a way for people always to get Office through the browser, which is very important. And we’ll see what we see in the future.” But Microsoft has another reason, aside from pushing the cloud version of Office, to de-emphasize the prospect of its productivity software on iOS. In a bid to draw more customers to its new hardware, Microsoft preloaded its Surface RT tablets with Office; offering the software on a rival touch-screen would take a major selling point off the table. Despite the billions it could earn from such an initiative, and despite rumors over the past several quarters that the software was indeed in the works, it’s also possible that Microsoft could be holding off Office for iOS for the time being.   Image: Microsoft