Phia co-founders accused of deliberately inflating affiliate commissions through cookie stuffing

A Bloomberg investigation found that Phia, an AI-powered shopping assistant founded in 2025 by Phoebe Gates and Sophia Kianni, deliberately used software features to place tracking cookies on users' browsers without genuine referrals. Internal Slack messages show the executives were aware of the practice, known as “cookie stuffing,” as early as December 2025 and discussed expanding it to increase monetization.

The company’s browser extension, which claims to locate the lowest-priced clothing items across multiple retailers, normally earns commissions when a user completes a purchase through a tracked referral. The investigation identified a “passive trigger” that dropped cookies every two hours on sites previously visited by users, and another mechanism that placed cookies whenever a shopper interacted with a Phia pop-up on a checkout page, even if the pop-up was closed.

"We are reviewing every transaction, we are fully committed to and have already begun issuing all transaction reversals to brand partners as a result of any misattribution, and we are hiring a head of compliance to make sure something like this never happens again," a Phia spokesperson said.

Phia removed the disputed features on July 7, after which its average daily revenue fell from roughly $80,000 to between $10,000 and $28,000. Under U.S. federal law, cookie stuffing is prosecuted as wire fraud, carrying a maximum sentence of 20 years in prison along with potential fines and restitution.