As companies old and new rush to capitalize on AI, many AI startups say their revenue is not only growing, but accelerating, hitting the next milestone in short periods of time.
The following list of startups reported a flywheel growth pattern. One thing to note is that the basic metrics used by these companies differ, even if they use the term “ARR.” Others may refer to annual recurring revenue (ARR), or revenue under contract from a paying but unpaid customer. Others refer to the annual income operating ratio, or to express annual income by calculating 12 months of continuous income at the most recent month’s rate. Others refer to “committed ARR,” or signed contracts from customers who have not yet signed in. In Gusto’s case, it reported actual revenue after 12 months.
However, each of these startups, listed in chronological order of when their ARR growth was made public, reports that their revenue growth is increasing, but they explain it. To be sure, there are many more fast-growing AI startups than we’ve mentioned here, but we’re limiting this list to companies that are hitting revenue milestones at the fastest rates.
Mercor: On Monday, Brendan Foody, founder and CEO of Mercor, announced that the company has surpassed $2 billion in annual revenue since June — just four months from reaching the $1 billion milestone. The less than three-year-old firm, which hires domain experts to train and refine AI models, said it hit a $500 million run in September.
Anthropic: In recent months, this model maker’s revenue has been at such a historic pace that it has stunned the entire AI industry. In late May, Anthropic announced that it surpassed $47 billion in revenue, a milestone that came less than two months after the company reported that the same metric surpassed $30 billion. The company said it will reach $9 billion in revenue by the end of 2025, up from $4 billion in July 2025.
Sierra: After reaching its first $100 million in ARR in seven quarters, Sierra—which builds AI agents for enterprise companies—says it took just two quarters to add another $100 billion in revenue, 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 seven years for the AI startup nine months to double its ARR from $100 million to $200 million, the company says it needed just six months to grow that metric from $200 million to $300 million.
Gusto: The 14-year-old HR technology startup announced in May that its revenue has grown at a faster pace in each of the past five quarters. The company, which maintained a $9.3 billion valuation at the start of 2022, also reported that it surpassed $1 billion in trailing 12-month revenue. Gusto’s capital increase shows that it’s not just native AI companies that are seeing their top growth largely charged by integrating the technology.
Clio: The 18-year-old provider of legal practice management software saw its revenue take off significantly after embedding AI in its offering by 2023. The company surpassed $200 million in ARR by mid-2024, doubled that figure late last year, and recently announced that its ARR reached $500 million.
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