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The era of the retroactive audit: From gray areas to $17M in bills

by Sarah Craig March 19, 2026

In the fast-moving world of SaaS and digital marketplaces, businesses sometimes make the dangerous assumption: if the law doesn’t explicitly name my business model, I don’t have to collect sales tax.

For years, many modern businesses have treated tax compliance as a wait-and-see game, assuming that they can fly under the radar until the legislation catches up to the technology. But a landmark 2026 ruling against StubHub has just sent a $17 million shockwave through the industry, proving that wait-and-see is a gamble most businesses can’t afford to lose.

The StubHub case: When clarification becomes retroactive

The dispute centered on ticket sales made on StubHub between 2008 and 2013. StubHub argued that during those years, Wisconsin’s tax laws were ambiguous. They claimed they weren’t a seller in the traditional sense, but rather a passive facilitator, an auctioneer of sorts, connecting buyers and sellers.

However, the Wisconsin Court of Appeals disagreed. In a January 2026 ruling, the court held StubHub liable for $17 million in back taxes, interest, and penalties. The most alarming part for modern founders? The court used a 2019 marketplace provider law to justify the bill. While StubHub argued this law was a new obligation that shouldn’t apply to the past, the court ruled that the 2019 law was merely a clarification of what the state always intended. By framing the new law as a clarification rather than a change, the state was able to reach back over a decade to collect.

The new trend: The five-year lookback

The StubHub ruling isn’t an isolated incident; it’s part of a growing trend of retroactive enforcement.

Look at the recent settlement involving SKIMS, a popular shapewear brand. In early 2026, SKIMS agreed to a $200,000 settlement with New Jersey over allegations of improperly handling sales tax clothing exemptions between 2019 and 2024. 

Whether it’s a marketplace like StubHub failing to collect, or a direct-to-consumer giant like SKIMS over-collecting due to technical errors, the message from state auditors is clear: they are looking back five or more years, and they will find the inconsistencies. 

This is where a sales tax solution like TaxJar helps. Once you categorize your products in TaxJar, we automatically apply sales tax when it is required, and exempts it when it’s not.

Tax laws can be reinterpreted 

If you are a SaaS founder or a marketplace operator, you might think your sales tax obligations are minimal or non-existent because your state hasn’t issued a specific bulletin on your niche business model yet. The StubHub case proves that states don’t need a new law to audit you, they can re-interpret an old one.

When a state decides you should have been collecting five years ago, you are left dealing with:

1. Back tax: This is the tax you should have been collecting from customers over the five year period. Which often comes out of your profit because you didn’t collect it from the customer.
2. Compound interest: Oftentimes, states will charge interest on top of tax owed. Which, after many years, can nearly equal the tax itself.
3. Negligence penalties: In StubHub’s case, the court reinstated a 25% penalty because they should have known based on general guidance.

How to protect your business 

The reality is that manual tax management is a significant burden for modern, multi-state businesses. It’s not scalable to spend your time reading every obscure tax bulletin or anticipating how a court might clarify a law in 2030.

This is where a solution like TaxJar becomes a business necessity. TaxJar automates the entire lifecycle of sales tax:

• Real-time calculations: Ensuring you’re charging the right amount at checkout, based on the latest state rulings and rate changes. TaxJar supports industries such as ticketing and events, as well as retail. Tax data is applied in real time, with 99.999% historical uptime — ensuring the right rate is applied for every transaction.
• Sales tax obligations monitoring: Alerting you when you are approaching a threshold to collect sales tax in a new state, so you never have a missing year of filings.
• Automated filing and remittance: Managing the actual filing and remittance, ensuring you stay in good standing with the state tax authorities. With a 100% on-time filing rate in 2025, TaxJar submits your returns on time, every time. 

Whether you’re a high-growth SaaS platform or a rapidly scaling marketplace, TaxJar gives you the confidence to grow without the looming shadow of an audit.

Ready to take the guesswork out of sales tax and protect your brand? Start your free 30-day trial or contact our team to schedule a demo of our product. 

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