Seattle Mayor Katie Wilson has signed a law barring large grocery retailers and delivery services from using customers’ personal information to set individualized prices, making Seattle the first U.S. city to prohibit the practice, city officials said. The measure covers data such as a person’s race, gender, online searches and social media history. It does not apply to grocery chains with fewer than 20 locations, convenience stores or farmers markets. The law takes effect Sept. 1, 2027. Wilson signed the legislation Monday after the City Council approved it 7-2. Councilmembers Bob Kettle and Maritza Rivera voted against it. Grocery industry representatives strongly opposed the proposal during hours of debate at multiple council meetings. At the signing ceremony, Wilson said rising costs for essentials including food are putting pressure on households, while some corporations are seeking new ways to profit. Councilmember Alexis Mercedes Rinck, who advanced the bill, described it as a response to corporate power and the affordability crisis. The practice, often called algorithmic price discrimination, can be difficult for shoppers to detect because customers typically see only the price they are charged. Councilmember Rob Saka, a co-sponsor with Councilmember Dionne Foster, said price changes driven by algorithms can leave grocery workers dealing with customers’ confusion and frustration. City Attorney Erika Evans said her office can subpoena records to investigate potential violations. The law also gives individuals a private right of action, allowing them to sue companies they believe have broken the rules. Evans said the measure does not prohibit coupons. She characterized it as a transparency and fairness rule intended to prevent personal data and artificial intelligence from determining what customers pay. Supporters at the signing included representatives of grocery workers union UFCW 3000, labor council MLK Labor and advocacy group WA People’s Privacy.