What are “directly connected” expenses?

Question: What are “directly connected” expenses?

Answer: Deductions incurred solely because of the unrelated business are known as directly connected expenses. These are expenses that wouldn’t be incurred if the unrelated business didn’t exist. 

For example, the costs of maintaining a building that’s used solely for a gift shop (the unrelated business) could be a directly connected expense. Salaries of full-time employees hired solely to operate the unrelated business would also be directly connected expenses.