Several of the largest property management companies operating in Seattle conspired to drive up rents and decrease competition, three lawsuits filed this month allege. The cases, filed in federal court in Seattle, focus on the use of RealPage software, which gathers information about rental units and rent prices and uses an algorithm to recommend how much landlords should charge. The complaints claim that by exchanging detailed and “competitively sensitive” information, RealPage and the landlords have illegally created a “cartel” to set prices in violation of antitrust laws. The widespread use…