This feature is expected to be available in the first half of 2017, both cointelegraph and MSPowerUser talked about this.
https://mspoweruser.com/bitcoin-currency-format-support-coming-soon-microsoft-excel-desktop-mobile/
This is an interesting news for financial analysts and its also good that the popularity of bitcoin is actually getting the people or organizations that matter. With my little knowledge of Excel which to my understanding, is more or less the basis of all financial models and experts around the world believes so, then this new feature will even get audience among the analysts that will arose another discussion in that regard. Good news all the way...