As companies new and old rush to capitalize on AI, many AI startups say their revenues are not only growing, but accelerating rapidly, reaching their next milestones in shorter periods of time.

The following list of startups has reported such a growth pattern. One thing to note is that the underlying metrics used by these companies differ, even if they use the term “ARR.” Some may refer to annualized recurring revenue (ARR) or revenue under contract from a paying customer but not yet billed. Some refer to income at an annualized rate or to projecting annual income by calculating 12 months of income continuing at the rate of the most recent month. Others refer to “committed ARR” or contracts signed by customers who are not yet onboarded. In the case of Gusto, it reported actual revenue for the last 12 months.

However, each of these startups, listed in reverse chronological order to when their ARR growth was made public, reports that their revenue growth is accelerating, no matter how they define it. There are certainly many more fast-growing AI startups than we name here, but we’re limiting this list to companies that are hitting revenue milestones at an increasingly rapid pace.

Mercor: On Monday, Brendan Foody, co-founder and CEO of Mercor, announced that the company had surpassed $2 billion in annualized gross revenue through June, just four months after reaching the $1 billion milestone. The less than three-year-old company, which hires domain experts to train and refine AI models, said it hit a $500 million run rate in September.

Anthropic: In recent months, this model maker’s revenue has reached such a historic speed that it has hypnotized the entire AI sector. In late May, Anthropic announced that it surpassed $47 billion in revenue run rate, a milestone that came less than two months after the company reported that its revenue run rate surpassed $30 billion. The company said it reached a revenue rate of $9 billion by the end of 2025, up from $4 billion reported in July 2025.

Saw: After reaching its first $100 million in ARR in seven quarters, Sierra, which creates customer service AI agents for businesses, says it only took two more quarters to add another $100 million, co-founder and CEO Bret Taylor announced in late May.

Glean: In May, Glean announced that it had surpassed $300 million in ARR. While it took the seven-year-old enterprise AI startup nine months to double its ARR from $100 million to $200 million, the company says it only needed six months to increase that metric from $200 million to $300 million.

Enthusiasm: The 14-year-old human resources technology startup announced in May that its revenue accelerated in each of the last five quarters. The company, which was last valued at $9.3 billion in early 2022, also reported surpassing $1 billion in trailing-12-month revenue. Gusto’s revenue growth shows that it’s not just AI-native companies that are seeing their revenue growth boosted by integrating the technology.

Clio: This 18-year-old legal practice management software provider saw a strong increase in revenue after incorporating AI into its offering in 2023. The company surpassed $200 million in ARR in mid-2024, doubled that figure late last year, and recently announced that its ARR reached $500 million.