Running from the Tax Man (to Fund One)
The bagel tells the story. In New York, a whole bagel is tax-exempt. Slice it, and suddenly it's "ready to eat" - taxable. Sam Ross knows this fact the way a surgeon knows anatomy: not because he read it in a textbook, but because he lived in the absurdity it represents. He was selling products in 47 states, spending ten hours every month navigating rules precisely this strange, when the question arrived uninvited: what if software just handled this?
That question became Numeral. But nothing about the path there was obvious, and Sam has the receipts to prove it.
He graduated from UCLA around 2011 with a stint at Bologna for good measure - the kind of educational biography that suggests a person collecting experiences rather than credentials. He moved through Teespring as a growth product manager before landing at Airbnb in June 2016, where he spent nearly two years working on growth under Gustaf Alstromer, a man who would later become a Y Combinator partner and a pivotal voice in Sam's founding story.
"The misconception with growth is that it doesn't matter if you don't have good retention."- Gustaf Alstromer's advice to Sam Ross, which Sam admits he ignored
At Airbnb, Sam absorbed a specific way of thinking about product growth - the B2C discipline of measuring activation, retention, and compounding loops with obsessive precision. He also got a lesson he wasn't ready to receive. Gustaf told him, clearly, that growth without retention was theater. Sam filed it away, then proceeded to ignore it when he left Airbnb in 2018 and started building ecommerce brands on his own terms.
He built a jewelry store. He launched a vitamin DTC site. He scaled Fling into eight figures. He was running these businesses from the road - actually traveling the world, funding the lifestyle through commerce. The brands worked. They made money. And then the sales tax notices started arriving.
Post-2018, the Supreme Court's South Dakota v. Wayfair decision changed the ground rules for online sellers. Suddenly, economic nexus meant a business selling into a state - without a physical presence - could owe that state sales tax. Forty-seven states with sales tax, forty-seven sets of rules, rates, thresholds, and filing deadlines. For an eight-figure DTC operation run by one person from a laptop in Lisbon or wherever, this was not a manageable problem. It was a ten-hours-per-month problem.
His barista spent 25 seconds on latte art. Sam watched, said nothing, and immediately calculated: eliminate the flourish, and throughput jumps from 100 to 120 cups per hour - a 20% efficiency gain. He didn't ask the barista to stop. But he did build a company around the idea that repetitive, measurable processes shouldn't consume human attention.
The ecommerce businesses were profitable. They were scaling. They were also, in Sam's own words, not billion-dollar outcomes. When Gustaf, now at YC, encouraged him to apply - not with his DTC brands, but with software built around the sales tax problem he'd been living - Sam listened this time.
Numeral was accepted into Y Combinator's Winter 2023 cohort. The pitch was simple in the way that all good pitches are simple: sales tax compliance is broken for ecommerce businesses, the regulatory landscape has only gotten more complex since 2018, and AI can do what accountants and spreadsheets can't - monitor every rate change, register in every state, file every return, automatically. End-to-end. Invisible to the merchant.
Boring by Design. Brilliant by Necessity.
Sam describes Numeral as "the most boring AI company." He says it like a badge of honor. The insight behind the label is sharp: boring problems, reliably solved, at scale, are often the most defensible businesses. Sales tax is not glamorous. It is, however, unavoidable - and getting more complex every legislative session.
His co-founder Matt DuVall built Stripe Checkout and Stripe Radar before leading teams at Notion. Sam brought the growth intuition and the merchant empathy. Matt brought the infrastructure credibility. The combination landed them in front of Benchmark Capital, which led their Series A in March 2025. That round closed in four days.
Four days. Not four weeks. Four days, because the underlying metrics were compelling enough that due diligence felt like a formality. Numeral had achieved 3.5x revenue growth in a year, processed over $5 billion in transactions, and was filing tax returns for more than 2,000 businesses including some of the most recognizable DTC brands in the country: Eight Sleep, Ridge, Graza, Nomad. The platform had registered clients in 47 states and filed 150,000+ returns. When the numbers look like that, investors don't need a second meeting.
Six months later, in September 2025, Mayfield led a $35 million Series B at a $350 million valuation. Benchmark returned. Y Combinator returned. Mantis came in new. Total funding crossed $71 million. The company that started as a fix for a founder's personal tax headache was now the infrastructure layer that thousands of ecommerce businesses depended on to stay compliant.
"Turns out, sales tax and VAT have gotten so complex that we need AI and millions of dollars in VC funding to make it simple again."- Sam Ross, on Numeral's Series B announcement
The business model has a quiet elegance. Numeral integrates with Shopify, Amazon, and the major selling platforms. It monitors nexus thresholds so clients know when they're required to collect and remit. It handles state registration, rate changes, return filing, and payment remittance - the full stack. And as merchants scale internationally, Numeral extends to VAT compliance across global markets. One platform. One team to call if something goes wrong.
The marketing story Sam told publicly about Numeral's lead generation is worth noting on its own. He generated so many inbound leads from a single piece of content that he had to temporarily turn off the marketing campaign. Not pause it for budget reasons. Turn it off because demand outpaced the team's capacity to onboard clients. That is a problem most founders would gladly have - and most never do.
B2C Instincts in a B2B World
Sam's party trick - and it's a real one - is applying consumer growth logic to enterprise sales problems. Most B2B founders think in pipelines and conversion rates. Sam thinks in activation curves and retention cohorts. The vocabulary is different. The underlying question is the same: why do customers stay, and how do you get more of them to the moment they understand why they should?
He talks about this publicly, on podcasts and in writing. In 2025 alone he appeared on The Peel with Turner Novak, discussing his growth playbook from the Airbnb years and how it shaped Numeral's go-to-market motion. The central thesis: in B2C, you learn fast because users churn fast. The feedback loop is brutal and immediate. B2B founders often lack this - they have longer contracts, murkier signals, and the comforting illusion that a customer who hasn't left yet is a customer who is happy. Sam doesn't believe that. He instruments Numeral like a consumer app: time-to-value measured in hours, not onboarding months.
The joke about his executive coach belongs in this context. A rival CEO was seeing the same coach. Sam's response, posted publicly: "I'd pay my coach double - if she gave the rival CEO terrible advice." It's funny. It's also a window into how Sam thinks about competitive advantage. Not as a zero-sum resource war, but as an information game. If your competitor has the same coach, the same investors, the same tool stack - the edge is in how you use them.
The Small Print
His Twitter handle is @spamross - a wordplay on his first name he's clearly committed to.
The Supreme Court's 2018 Wayfair decision didn't just change tax law - it created the market that made Numeral possible.
He was running DTC brands from the road while traveling internationally before founding Numeral - the problem he was solving was literally his own.
His co-founder Matt DuVall built Stripe Checkout and Stripe Radar - two products that are now table stakes for online commerce.
Gustaf Alstromer, who pushed Sam toward Numeral, was Sam's manager at Airbnb before becoming a YC partner - a mentorship that shaped two chapters of his career.
Numeral processed over $5 billion in transactions and filed 150,000+ tax returns - the equivalent of a medium-sized accounting firm, automated.