The Justice Department is thrusting the largest rental property managers into the spotlight as it expands a price-fixing lawsuit alleging widespread collusion in the housing rental market. In an amended lawsuit against RealPage Inc.

The DOH had sued property management software company RealPage of letting landlords collude by sharing their pricing information with the company's software, which then recommends rent prices.

The U.S. Department of Justice has accused several Houston-area landlords of colluding to inflate rent prices, expanding its antitrust case against RealPage, a Texas-based company whose software at the center of an alleged rent price-fixing effort.