Round-Trip Trading

What Does Round-Trip Trading Mean?
An action that attempts to inflate transaction volumes through the continuous and frequent purchase and sale of a particular security, commodity or asset. Round-trip trading can be used to refer to the practice of a business selling an unused asset to another company while agreeing to buy back the same asset for about the same price (which has been seen in the energy and telecom business). 

Investopedia explains Round-Trip Trading
This is a market-manipulation practice used to misrepresent the number of transactions occurring on any given day. Round-trip trading artificially inflates volume and revenues, but in reality adds no profit. Enron was a company that engaged in round-trip trading, and, by doing so, was able to increase revenues (and expenses) without changing its net income.