Sphere has secured a $21 million Series A funding round led by Andreessen Horowitz, with participation from Y Combinator and Felicis Ventures, marking a significant milestone for the AI-driven cross-border tax compliance company. The investment reflects rising demand for automated, scalable tax infrastructure as businesses expand internationally earlier and face heightened regulatory scrutiny.
Regulators across key markets are implementing stricter reporting requirements, and many governments are shifting toward real-time digital submissions for tax data. At the same time, technology companies are increasingly global from inception, with a recent Stripe study showing that most startups sell into more than ninety countries by the end of their second year.
Founded by Nicholas Rudder, Sphere initially focused on indirect tax, including sales tax, VAT, and GST. It has since emerged as a critical compliance partner for global finance teams at companies such as Lovable, Replit, Windsurf, Deel, and Eleven Labs. The company attributes its growth to two product differentiators: direct digital connections into more than one hundred tax authorities worldwide and its proprietary AI-native Tax Review and Assessment Model, or TRAM.
Sphere’s infrastructure was built in stealth over eighteen months and enables end-to-end automation of registrations, calculations, filings, and remittances across jurisdictions. TRAM continuously collects and codifies global tax rules, automating research that traditional vendors still execute manually. The model is trained with extensive expert feedback and maintains experts in the loop for accuracy and refinement.
The new funding will support Sphere’s plans to expand TRAM beyond indirect tax into areas such as input tax, withholding, e-invoicing, and tariffs, advancing its ambition to become a full revenue-based compliance engine.
The investment follows a year of rapid momentum. Since emerging from stealth in late 2024, the company has sustained average monthly revenue growth above thirty percent and added global customers across the technology sector. Sphere has also deepened its ecosystem partnerships, becoming one of only three tax vendors worldwide with a native integration into Stripe Billing and Stripe Checkout, while also joining the NetSuite SuiteCloud Developer Network. On the product front, Sphere recently expanded TRAM’s indirect tax coverage for both tangible and digital goods and introduced embedded global tax remittance across more than one hundred regions.
Customer feedback has highlighted the benefits of Sphere’s unified automation approach compared with legacy solutions that rely on networks of local service providers. The company believes its AI-native architecture and international reach deliver a more scalable pathway for global expansion.
KEY QUOTES
“Sphere isn’t just another vendor – it’s a scalable platform built for the next era of compliance. Just as Deel redefined global payroll, Sphere is transforming revenue-based compliance. With the right technology, team, and timing, they’re poised to solve indirect tax and broader cross-border compliance on a global scale.”
Marc Andrusko, Partner at Andreessen Horowitz
“We were using another tax vendor that outsourced some of their international functionality to a network of local service providers. Managing that patchwork of local representatives created a lot of administrative load, incurred significant fees and simply wasn’t scalable. Sphere automates the entire end-to-end compliance process on one platform giving us peace of mind as we scale.”
Adam Strouss, Vice President of Finance at Windsurf
“This funding allows us to accelerate our vision of building the first AI-native cross-border compliance engine. When you think about an area like tax – whether it be indirect tax, withholding tax, tariffs – it’s really just a massive document based problem. The rules are all available online, just in unstructured formats, hard to find places and different languages. Understanding how those rules apply to your business is a problem well suited to AI as long as the right guardrails are in place. Our scalable research and true international capabilities keep customers compliant, saving them time and money, and unlocking new markets. Sphere makes selling globally as easy as selling locally.”
Nicholas Rudder, Founder of Sphere
