Your personal data, including your precise location, browser history, and even your mouse movements, is being used by some companies to show different prices for the same products—a phenomenon the FTC has dubbed “surveillance pricing.”

According to a new FTC report, retailers are hiring “intermediary firms” to algorithmically tweak and target their prices.

“Instead of a price or promotion being a static feature of a product, the same product could have a different price or promotion based on a variety of inputs—including consumer-related data and their behaviors and preferences, the location, time, and channels by which a consumer buys the product,” the FTC says.