Micron, Supermicro, Lenovo, and Hewlett Packard Enterprise (HPE) are all subjects of a U.S. International Trade Commission (USITC) investigation into the importation of alleged patent-infringing memory hardware.

California-based Netlist brought the action, alleging the quartet imported products that infringe four of its patents covering innovations related to server-grade memory modules, including DDR5 RDIMM and MRDIMMs. The patents cover innovations like on-module power and clock signal management.

A patent owner can ask the USITC to launch a Section 337 investigation, which probes imports of alleged intellectual property-infringing goods. If a violation is found, the big tech quarter could face a ban on importing at-issue goods.

Netlist has asked the agency to impose a cease-and-desist order, which would bar the sale of already imported goods that infringe its patents.

Section 337 probes typically conclude within less than 15 months. Officials must set a target date for completing their investigation within 45 days after it is instigated.

One of the four companies subjected to the USITC investigation has been in Netlist’s crosshairs for some time. Micron was previously sued by the company for patent infringement, with jurors in a Texas court finding infringement had taken place and that it owed Netlist $445 million in damages.

Micron has since tried to fight back, arguing Netlist was a “patent troll,” a pejorative business practice in which companies buy patents just to sue other businesses for money.

In addition to its bad-faith argument, the big memory trio member has sought to have Netlist’s patents invalidated, of which several have been successfully struck out by the Patent Trial and Appeal Board, which the Federal Circuit affirmed in early September. Its wider efforts to try and unravel the $445 million damages is still pending.

This latest action before the USITC involves different patents from the prior action.

Samsung, which was also the subject of a Netlist lawsuit, also tried to get patents invalidated – while also alleging it stole tech from Intel. The pair ultimately settled, with Samsung agreeing to pay Netlist licensing fees that could rise as high as $898 million as part of a five-year deal.

Following its latest action, Netlist CEO C.K. Hong said: “The Samsung agreement established an important industry benchmark for the value of our IP. We intend to continue our enforcement efforts against unauthorized users such as Micron.”