Last week, Google (NASDAQ:GOOGL) announced that it's making QuickOffice free. The search giant acquired the popular mobile productivity suite last year and has relaunched it under its multi-colored umbrella. Meanwhile, Apple also just said it will include iWork for iOS for free on all new iOS devices.

Microsoft's (NASDAQ:MSFT) Office cash cow has had trouble making the shift to mobile platforms, and the company's current offering is available only for paying Office 365 subscribers. With Apple and Google offering free alternatives on the consumer level, Microsoft may have a tough sell.

On the other hand, Microsoft's core Office market is the enterprise. Google is attacking that market with Google Apps for Business, but Apple has little to no interest in the enterprise productivity software market. The office business is Microsoft's most profitable by far, so it potentially has a lot to lose if these threats escalate even further.

In the following video, Erin Kennedy discusses the risks to Microsoft with Evan Niu, CFA.

Erin Kennedy and Evan Niu, CFA, both own shares of Apple. The Motley Fool recommends Apple and Google and owns shares of Apple, Google, and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.