The Department of Justice's Antitrust Division opened an investigation into real estate tech company RealPage and its rent-setting software, ProPublica reports, citing an unnamed source familiar with the matter.

The company's YieldStar software allegedly allows landlords to inflate apartment rents beyond competitive levels.

The DOJ investigation comes in the wake of congressional pressure to open an investigation into the Dallas-based company, which came in the form of letters to the Justice Department and the Federal Trade Commission.

A class-action lawsuit was filed in the Southern District of California on behalf of all multifamily renters whose landlords have used RealPage tech. The lawsuit accuses the company of sharing price information in such a way that it essentially forms a cartel whose goal is higher rents.

Besides RealPage, major landlords such as Greystar Real Estate Partners, Lincoln Property Co., FPI Management, MAA, Equity Residential, Essex Property Trust and Security Properties were among those named in the suit.

A separate suit brought this month by a University of Washington student in Seattle federal court alleges that commercial real estate firms, including Greystar Real Estate Partners and Cushman & Wakefield, colluded by using RealPage’s YieldStar to set artificially high prices for student housing rentals.

RealPage has denied the allegations.