"The noble families mainly," said Honeydew. "After the civil war their agreement with Twilight Sparkle left them in a position to purchase the old industries that had been under the Duke's control, or develop new ones using the ideas coming in from Equestria. Since the current government was in no position to do this themselves at the time, it was seen as a benefit to both sides as making Mareitania functional was the main goal at the time. Of course the government does have its own privately owned industry, such as the tank factory you destroyed, but a lot of the others are owned by the noble families."