Phia, the shopping startup co-founded by Phoebe Gates, daughter of Microsoft co-founder Bill Gates, is facing scrutiny over allegations that it used a controversial affiliate-marketing technique known as “cookie stuffing” to claim commissions on purchases it may not have generated.
The allegations, reported by Bloomberg, have put the young company under pressure because affiliate attribution sits at the heart of its business model. Phia has said it removed features that could cause misattributions, is reviewing transactions and plans to strengthen its compliance processes.
The dispute also highlights a broader problem for AI-powered and data-driven shopping platforms: when technology determines which company gets credit for a sale, a seemingly small technical feature can have direct financial consequences for retailers, affiliates and consumers.
What is cookie stuffing, and why is it controversial?
Cookie stuffing is an affiliate-marketing practice in which tracking information is placed on a user’s browser without a legitimate referral from the affiliate.
Normally, the process is straightforward. An affiliate sends a shopper to a retailer through a tracked link. If the shopper makes a qualifying purchase, the affiliate can receive a commission because it legitimately referred the customer.
Cookie stuffing can disrupt that system by creating the appearance of a referral even when the affiliate did not meaningfully drive the purchase.
That matters because affiliate programs generally pay commissions based on attribution. If one platform improperly receives credit, another affiliate that actually influenced the purchase can lose the commission.
How affiliate attribution normally works
A simplified affiliate transaction looks like this:
- A shopper discovers a product through an affiliate.
- The shopper clicks a tracked referral link.
- The retailer records the referral.
- The shopper eventually makes a purchase.
- The affiliate receives a commission if the transaction meets the program’s rules.
Cookie stuffing can interfere with that chain by inserting tracking data without the kind of referral activity the affiliate program intended to reward.
What is Phia accused of doing?
According to Bloomberg’s reporting cited in the supplied material, Phia was accused of using cookie stuffing despite contractual restrictions against the practice.
The investigation reportedly found that Gates and co-founder Sophia Kianni were aware of the startup’s involvement in the practice as early as December 2025.
The allegations are particularly significant because the practice reportedly represented a meaningful portion of Phia’s sales. After it was stopped, the company experienced a sharp decline in daily revenue, according to the report.
Bloomberg also reported that retailers including Nike and Nordstrom were affected.
Phia initially characterized the behavior as a bug, but Bloomberg later reported that the feature had been intentionally designed and could be switched on or off.
Those competing descriptions are important. A genuine software malfunction and a deliberately built attribution mechanism raise very different questions about oversight, intent and compliance.
Why did Phia’s revenue reportedly fall after the practice stopped?
Affiliate businesses depend heavily on accurate attribution. If a platform receives credit for purchases it did not generate, removing that mechanism can produce an immediate decline in reported sales or commission-generating transactions.
That appears to be what happened at Phia, according to the Bloomberg investigation summarized in the supplied report.
The decline does not necessarily mean that every sale previously attributed to Phia was fraudulent. It does, however, raise a basic question about how much of the company’s reported commercial activity was being driven by legitimate referrals versus disputed attribution.
For a young startup, that distinction can be enormous.
Revenue figures can influence investor confidence, retailer relationships and perceptions of whether a business model is actually working. If a substantial portion of those numbers depends on an attribution mechanism that later has to be removed, the company’s underlying performance can look very different.
What has Phia said about the allegations?
Phia has disputed some of the claims while acknowledging that it needs to learn from the episode.
A company spokesperson told Bloomberg that features responsible for misattributions were removed on July 7. The company also said it was reviewing transactions and had begun issuing reversals to brand partners where misattribution occurred.
That response suggests Phia is treating the issue as more than a software problem. Reviewing historical transactions can help determine which purchases were incorrectly attributed and whether affected brand partners should be compensated.
The company has also said it plans to hire a head of compliance.
That appointment could become an important test of whether Phia is building formal controls around its technology as it grows.
Why does the controversy matter beyond Phia?
The dispute is bigger than one shopping startup because affiliate marketing is a major part of the online commerce ecosystem.
Consumers increasingly discover products through search engines, social media, recommendation platforms, browser tools and shopping apps. Behind those seemingly simple recommendations can be complicated networks of referral agreements and tracking systems.
When attribution goes wrong, the consequences are not always visible to shoppers.
A customer can make exactly the same purchase at exactly the same price while the financial beneficiary behind the transaction changes.
That makes transparency especially important. A platform that recommends a product should not necessarily receive commission simply because its software happened to interact with the customer’s browser.
The compliance challenge for fast-growing startups
Phia’s situation also illustrates a recurring tension in technology companies: rapid experimentation can move faster than internal controls.
Startups often build features quickly, test different approaches and measure results. But financial attribution systems require particularly careful oversight because they affect third-party payments.
A strong compliance framework should establish:
- Who can approve changes to tracking systems.
- How affiliate attribution is tested.
- Whether users have knowingly triggered tracking mechanisms.
- How suspicious transactions are identified.
- How retailers can audit disputed referrals.
- How technical changes are documented and reviewed.
Without those safeguards, a feature intended to improve conversion or tracking can create substantial legal and commercial risk.
Who are Phia’s founders?
Phia was co-founded by Phoebe Gates and Sophia Kianni and launched in 2025 as a shopping platform designed to help users find and compare products.
The company was positioned as a more efficient way to navigate online shopping, with the supplied report comparing its concept to the way Google Flights simplifies travel searches.
Gates’ family background has also guaranteed significant public attention. She is the daughter of Bill Gates, the Microsoft co-founder and philanthropist, making scrutiny of her business ventures particularly intense.
But the central issue in this case is not her family connection. It is whether Phia’s technology accurately represented which transactions it generated and whether its affiliate relationships complied with contractual requirements.
Phia has faced other scrutiny
The cookie-stuffing allegations are not the only controversy surrounding the startup.
The supplied report says Phia has also faced criticism over allegations involving data collection and tracking user behavior across the web.
Those issues share an underlying theme: how much information a shopping platform collects, what it does with that information and how transparently those practices are disclosed.
For companies that operate at the intersection of shopping, advertising and consumer data, those questions are becoming increasingly important.
The more powerful the technology becomes, the more important it is for companies to explain what happens behind the interface.
What happens next for Phia?
Phia’s next steps will likely center on transaction reviews, retailer relationships and compliance.
The company says it has removed features responsible for misattributions and is reviewing transactions to determine whether brand partners were incorrectly charged or credited.
The planned hiring of a head of compliance could also signal a move toward stronger internal controls.
For retailers and affiliate partners, the most important question will be whether Phia can demonstrate that future transactions are being attributed accurately and transparently.
For investors and users, the bigger question is whether the startup’s underlying shopping model remains strong after disputed attribution is removed from the equation.
The bigger lesson from the cookie-stuffing controversy
The Phia controversy demonstrates why affiliate attribution is not merely a technical detail.
Behind every commission is a claim that a particular platform, publisher or creator helped generate a sale. When tracking technology changes that attribution, money changes hands as well.
That makes accuracy and transparency essential.
Phia now has an opportunity to show that it can separate legitimate innovation from practices that undermine trust in the affiliate ecosystem. Its transaction review, promised compliance leadership, and dealings with affected retailers will be important indicators of how the company responds.
The episode also offers a lesson for the wider startup industry: growth metrics are only as credible as the systems used to produce them.
