Bloomberg found Phia's extension replaced affiliate codes without user clicks. The startup fixed the bug. Impact.com suspended its account. Investors include Kleiner Perkins and Khloe Kardashian.
Phia, the shopping startup co-founded by Phoebe Gates, daughter of Microsoft co-founder Bill Gates, is under investigation after Bloomberg reported its browser extension improperly claimed affiliate commissions through cookie stuffing.
The practice involves placing an affiliate tracking cookie on a user's browser without a legitimate click. If the shopper later completes a purchase, the cookie's owner gets credit and a commission without driving the sale. Affiliate marketing experts told Bloomberg this violates the policies of most networks and retailers.
Phia launched in 2025 by Gates and Sophia Kianni. It describes itself as a personal shopping assistant, comparing prices and finding discount codes. The startup raised $43.5 million from Kleiner Perkins and Khosla Ventures, with celebrity investors including Sydney Sweeney, Khloe Kardashian and Hailey Bieber. Appfigures data cited by Bloomberg shows more than 1.2 million downloads over the past year.
Bloomberg tested the extension on more than 50 retail websites over a week. During checkout, the extension silently opened a hidden background browser tab that loaded Phia's affiliate link. Bloomberg observed the behavior across multiple affiliate networks, including Impact.com. The extension replaced referral codes on Walmart, Nike and Zara.
In one test, Bloomberg clicked a Nordstrom shopping link from Wirecutter. Before checkout, Phia replaced Wirecutter's tracking code with its own.
Capital One Shopping, a competing browser extension, warned retailers that Phia was generating "fake clicks" and engaging in cookie stuffing. In an email reviewed by Bloomberg, the company said: "Publishers like us are having material revenue taken. Advertisers like you are losing money to fake clicks." Capital One said it considered it its responsibility to alert retailers.
After Bloomberg contacted Phia, a spokesperson acknowledged the problem came from a recent software release. Engineers worked overnight to resolve it. The company said: "Within the last 24 hours, we were made aware that in a recent release our codebase was causing misattributions from a subset of users." Bloomberg retested and found the automatic referral replacement had stopped.
Phia said it undergoes regular audits by affiliate network partners and has "always maintained compliance." Impact.com said it suspended Phia's account after detecting behavior inconsistent with its policies. The network said it is reviewing affected transactions and working with Phia to determine corrective action.
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