AI startups are hitting revenue milestones in ever-shorter windows

A cluster of fast-growing startups — some AI-native, some not — say their revenue is not just growing but accelerating, hitting new milestones in shorter stretches of time with each round. The companies describe this using different metrics under the same “ARR” label: some report annualized recurring revenue from signed, paying contracts; others report annualized run-rate revenue, projecting a full year from the most recent month’s pace; still others cite “committed ARR,” from signed contracts not yet onboarded. Gusto is the exception, reporting actual trailing 12-month revenue. Many more fast-growing AI startups exist; this list is limited to companies whose milestones are arriving at an accelerating pace, ordered by how recently each was made public.

Mercor, a less-than-three-year-old startup that hires domain experts to train and refine AI models, said co-founder and CEO Brendan Foody announced this week that gross annualized revenue crossed $2 billion in June — just four months after the company passed $1 billion. Mercor said it had reached a $500 million run rate in September. Anthropic’s growth has moved even faster: the model maker said its revenue run rate crossed $47 billion in late May, less than two months after surpassing $30 billion. Anthropic had reported a $9 billion run rate in late 2025, up from a reported $4 billion in July 2025.

Sierra, which builds customer-service AI agents for enterprises, took seven quarters to reach its first $100 million in ARR, but co-founder and CEO Bret Taylor said in late May that the company added the next $100 million in just two more quarters. Glean, a seven-year-old enterprise AI startup, said in May that it had crossed $300 million in ARR; the company took nine months to double from $100 million to $200 million, but just six months to grow from $200 million to $300 million.

Not every accelerating company is AI-native. Gusto, a 14-year-old HR tech startup last valued at $9.3 billion in early 2022, said in May that its revenue growth had accelerated in each of the past five quarters and that trailing 12-month revenue surpassed $1 billion. Clio, an 18-year-old legal practice management software provider, saw growth take off after embedding AI into its product in 2023: ARR passed $200 million in mid-2024, doubled by late last year, and recently reached $500 million.

Why it matters

The pattern shows AI adoption compressing the time it takes software companies — not only AI-native ones — to scale revenue, raising the bar for what counts as fast growth in enterprise software.