Why is algorithmic rent-setting treated as illegal price-fixing?

Algorithmic rent-setting draws antitrust scrutiny when software feeds competing landlords' pricing and occupancy data into a shared algorithm that then recommends rents, since that can produce the same coordinated pricing effect as landlords directly agreeing on rates, even without a phone call between them. Regulators have argued this undermines the independent pricing decisions competition law is meant to protect. Whether a specific tool crosses that line is a legal question decided case by case, not something this site determines generally.