Phia's daily revenue fell 87% after cookie-stuffing halt

For retailers, every affiliate commission is a line item that should trace to a real, attributable sale — and Bloomberg's investigation into Phia suggests a high-profile case where that trace was broken at scale. The shopping-assistant startup co-founded by Phoebe Gates and Sophia Kianni allegedly used its browser extension to 'cookie-stuff' shoppers and collect commissions on purchases it never drove, with daily revenue plunging from $80,000 to as low as $10,000 once the practice stopped. The episode should put every merchant's affiliate program, and every discount-extension partner, under immediate audit.

Phia, the shopping-assistant startup co-founded by Phoebe Gates — daughter of Microsoft co-founder Bill Gates — and Stanford graduate Sophia Kianni, now faces the most damaging kind of allegation for a company built on consumer trust: that its founders knowingly engineered a scheme to collect commissions on sales it never influenced. According to a follow-up investigation published by Bloomberg on Tuesday, August 11, 2026, internal Slack messages and source code reviewed by the news organization indicate Gates and Kianni were aware for months that Phia's browser extension was automatically injecting affiliate tracking cookies into shoppers' online purchases, a practice known as 'cookie stuffing.' The report directly contradicts Phia's public position in July, when the controversy first surfaced, that the company had only discovered the problem within the previous 24 hours and had promptly corrected what it described as a software issue.

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After the automatic cookie features were disabled in July, Phia's average daily revenue reportedly fell from roughly $80,000 to between $10,000 and $28,000 — a decline of roughly 65% to 87%.

The mechanics of the alleged scheme matter enormously for the retail and affiliate-marketing ecosystem. In a typical affiliate program, a retailer pays a commission — often in the 5% to 20% range — to whichever partner's link or cookie is last in a shopper's click chain before a purchase. Coupon, cash-back and shopping-assistant extensions monetize by being that final touchpoint. Cookie stuffing subverts this model: a browser extension silently drops a tracking cookie even when a shopper never clicked a partner link or used a discount code, causing the merchant to pay a commission for a sale the affiliate did not actually generate. For retailers, this is not an abstract compliance problem; it is money leaking out of every affected order, and it erodes the data merchants rely on to judge which marketing channels actually work.

Bloomberg's reporting suggests the financial scale of the practice was substantial. After the automatic cookie features were disabled in July, Phia's average daily revenue reportedly fell from roughly $80,000 to between $10,000 and $28,000 — a decline of roughly 65% to 87%. Phia has said part of the drop stemmed from suspending other monetization tools, but even the most charitable reading implies that a large majority of the startup's revenue was tied to attribution that is now in question. That is a striking detail for the investors who poured 'tens of millions of dollars' into the company's first funding round from prominent Silicon Valley and celebrity backers, and for Bill Gates, who actively promoted the venture as his daughter sought to distance it from the 'nepo baby' label.

The legal exposure is equally serious. Cookie stuffing can constitute federal wire fraud, which carries a maximum sentence of 20 years. The reported Slack exchanges — in which Gates allegedly asked developers in December to ensure automatic cookie drops were working 'across retailers' so Phia could monetize 'every transaction,' and Kianni told engineers that 'whatever we can do to keep these cookies dropping will be amazing' — are the kind of evidence that transforms a technical glitch into a potential intent case. The 24-hours-versus-months discrepancy is not merely a public-relations problem; it goes directly to whether the founders knowingly misrepresented the situation to partners, investors and the public.