The value of Microsoft stock hit a five year high on Tuesday, closing at $33.10.
The new Xbox will be revealed to the public later this month, and it seems investors are betting on it being a hit.
Also bolstering Microsoft's value is the success of its enterprise and cloud service business.
The company posted $6 billion in profits for the third quarter.
In the past investors have been concerned that Microsoft didn't have anywhere to go; the company was the most valuable stock on the market at one point, and it seemed unrealistic to assume further growth.