A law enforcement action alleged that on several trading days over the course of two...

A law enforcement action alleged that on several trading days over the course of two months, defendants engaged in a series of copper gold, crude oil. and natural gas futures transactions on an electronic trading platform One defendant repeatedly bought future contracts at low prices from the other, and then immediately sold them back at higher prices. As a result, one defendant effectively pocketed the same amount as the other lost even though there were no changes in the open positions held by either defendant.

What is a name for this typology?