Rillet’s rapid rise is sharpening the threat AI poses to the software giants that have long dominated corporate accounting. But the startup’s pitch is not that accountants are obsolete; it is that an overstretched profession needs better tools.

Two years after emerging from stealth, Rillet raised $100 million at a $1 billion valuation, a round that came together in 48 hours after the company showed investors that its annualized revenue had doubled in a quarter. The startup says it now has 600 customers, including public companies, and has raised $200 million in total.

The momentum is being driven by a direct assault on incumbent systems. Chief executive Nicolas Kopp said customers are not merely testing the product: they are replacing software from Intuit, NetSuite and Oracle. About half of Rillet’s customers arrive from Intuit, while another 30% come from NetSuite and Sage Intacct, according to Kopp.¹

Investors see more than a narrow bookkeeping tool. Iconiq’s Seth Pierrepont said Rillet had already demonstrated that it could “win against the incumbents that have owned this category for decades.”¹ Sequoia’s Julien Bek went further, arguing that accounting is only the opening move toward reinventing the wider finance function.¹

Kopp’s counterweight to fears of automation is the industry’s labour crunch. Rillet is built to let accountants work alongside agents, automating repetitive tasks while retaining human oversight. For public-company work, he noted, every AI-agent transaction still requires human approval.

That distinction matters. Kopp said, “I just don’t see people losing their job anytime soon,” framing the software as a way to give finance teams more time for analysis and advice rather than a tool to erase junior roles.¹ The immediate contest, then, is not humans versus machines. It is whether legacy accounting platforms can keep customers from defecting as AI-native alternatives mature.