Landlords and property managers can’t collude on rental pricing. Using new technology to do it doesn’t change that antitrust fundamental. Regardless of the industry you’re in, if your business uses an algorithm to determine prices, a brief filed by the FTC and the Department of Justice offers a helpful guideline for antitrust compliance: your algorithm can’t do anything that would be illegal if done by a real person.

Today, the FTC and Department of Justice took action to fight algorithmic collusion in the residential housing market. The agencies filed a joint legal brief explaining that price fixing through an algorithm is still price fixing. The brief highlights key aspects of competition law important for businesses in every industry: (1) you can’t use an algorithm to evade the law banning price-fixing agreements, and (2) an agreement to use shared pricing recommendations, lists, calculations, or algorithms can still be unlawful even where co-conspirators retain some pricing discretion or cheat on the agreement.

The agencies’ work in this space is especially important given rising residential housing rental prices. Rent is up nearly 20% since 2020, with the largest increases concentrated on lower- and middle-tier apartments rented by lower-income consumers. About half of renters now pay more than 30% of their income in rent and utilities, and rising shelter costs were responsible for over two-thirds of January inflation.

Meanwhile, landlords increasingly use algorithms to determine their prices, with landlords reportedly using software like “RENTMaximizer” and similar products to determine rents for tens of millions of apartments across the country. Efforts to fight collusion are even more critical given private equity-backed consolidation among landlords and property management companies. The considerable leverage these firms already have over their renters is only exacerbated by potential algorithmic price collusion. Algorithms that recommend prices to numerous competing landlords threaten to remove renters’ ability to vote with their feet and comparison-shop for the best apartment deal around.

What’s the message for other businesses?

Agreeing to use an algorithm is an agreement. In algorithmic collusion, a pricing algorithm combines competitor data and spits out the suggested “maximized” rent for a unit given local conditions. Such software can allow landlords to collude on pricing by using an algorithm—something the law doesn’t allow IRL. When you replace once-independent pricing decisions with a shared algorithm, expect trouble. Competitors using a shared human agent to fix prices? Illegal. Doing the same thing but with an agreed upon, shared algorithm? Still illegal. It’s also irrelevant that the algorithm maker isn’t a direct competitor if you and your competitors each agree to use their product knowing the others are doing the same in concert.

Price deviations don’t immunize conspirators. Some things in life might require perfection, but price-fixing arrangements aren’t one of them. Just because a software recommends rather than determines a price doesn’t mean it’s legal. Setting initial starting prices or recommending initial starting prices can be illegal, even if conspirators deviate from recommended prices. And even if some of the conspirators cheat by starting with lower prices than those the algorithm recommended, that doesn’t necessarily change things. Being bad at breaking the law isn’t a defense.

The housing industry isn’t alone in using potentially illegal collusive algorithms. The Department of Justice has previously secured a guilty plea related to the use of pricing algorithms to fix prices in online resales, and has an ongoing case against sharing of price-related and other sensitive information among meat processing competitors. Other private cases have been recently brought against hotels and casinos.

Technology is a promise. Used correctly, it can make our lives healthier, safer, and more efficient. But its efficiency can also be used by bad actors to crush competition or bilk consumers in novel ways. No matter the tool law violators use, the FTC and the Department of Justice stand vigilant on the side of consumers and competition.

Hannah Garden-Monheit is Director of the FTC’s Office of Policy Planning and Ken Merber is Deputy Assistant Director of the FTC’s Anticompetitive Practices II Division.