Microsoft allows employees to buy software at cost for personal use, but prohibits resale. The company declined to say how many workers were disciplined or what actions it took.
The move comes after the Dec. 11 arrest of former Microsoft executive Daniel Feussner, who was accused of stealing software with an estimated retail value of $9 million from Microsoft.
Prosecutors allege he resold the software, using the proceeds to buy expensive watches, cars, a yacht, a motorcycle and other luxury items.
Feussner, 32, is free on bond, awaiting trial.