The news
Arceus Legal, a San Francisco law firm that uses artificial intelligence to do much of its work, has raised $17 million, SiliconANGLE reported on October 1, 2026. The Arceus Legal funding round was led by Greycroft, with Craft Ventures and South Park Commons also investing. The firm plans to expand beyond commercial contracts.
Arceus is not selling software to lawyers. It is a law firm that sells legal services to fast-growing companies, with licensed attorneys approving every piece of work. According to SiliconANGLE, those attorneys are assisted by AI agents and software the firm built itself.
The pricing is the pitch. Clients get a flat price quoted before a matter begins. SiliconANGLE reported that if a standard contract review runs past eight hours, the client does not pay for it, that most reviews finish in three to five hours, and that the service is listed at $500. Artificial Lawyer, a legal industry publication, described the same guarantee and said the firm carries the financial risk on its engagements.
The firm's internal system, called CounselOS, tracks each client's preferences, past agreements and negotiation history, according to SiliconANGLE. It connects to Salesforce, HubSpot and Gmail, routes matters to attorneys and sends status updates over Slack or email. Current work covers master service agreements, non-disclosure agreements, vendor deals, employment matters and privacy work.
Founder and chief executive Mac Liu told SiliconANGLE that he had cycled through several law firms before starting Arceus, running into missed deadlines and bills higher than expected. The billable-hour model, he said, "just didn't make sense to me because firms are incentivized to take longer." SiliconANGLE reported that the customer base quadrupled in September.
The new money will pay for hiring attorneys, engineers and AI researchers at the San Francisco headquarters as Arceus takes on more kinds of legal work, according to SiliconANGLE. Neither report named the round's stage or the company's valuation.
The numbers
- Funding raised
- $17 million
- Lead investor
- Greycroft
- Free-review threshold
- 8 hours
- Typical contract review
- 3–5 hours
- Listed review price
- $500
- Customer growth in September
- 4x (per SiliconANGLE)
Why CEOs should care
For general counsels and CFOs, Arceus is a different kind of vendor to put in the outside-counsel mix. Instead of buying a legal AI tool and asking in-house lawyers to use it, a company buys finished, attorney-approved work at a fixed price. That turns a variable legal bill into a line item that can be budgeted per contract. Worth testing on high-volume, low-risk work such as NDAs and vendor agreements, where the savings are easiest to measure against a current firm's invoices.
The questions to ask are about liability and data. Which attorneys sign off, in which states are they licensed, and what malpractice coverage stands behind the work? CounselOS stores negotiation history and links to CRM and email systems, so security and legal teams should ask what data the firm pulls in, where it is kept and whether it is used to train models. A flat price also needs a clear definition of "standard" so that unusual contracts do not get pushed into change orders.
Boards and finance leaders can use the offer as leverage. Even if a company keeps its incumbent firm, a $500 flat-fee benchmark for routine reviews gives procurement a number to bring to the next rate negotiation with any firm still billing by the hour.
The bigger picture
Much of the money in legal AI has gone to software sold to existing firms and in-house legal teams, the category where Harvey is the best-known name. Greycroft partner Mark Terbeek framed Arceus as the opposite bet: what SiliconANGLE quoted as "rebuilding the law firm itself."
That model puts the technology risk on the provider. If the AI makes a contract review faster, the firm keeps the margin; if a review runs long, the firm absorbs the cost. Whether that holds up as Arceus moves from routine contracts into areas like litigation, regulatory work or mergers, where scope is hard to price in advance, is the open question for the model.
What’s next
Arceus says it will expand beyond commercial contracts to cover a company's broader legal needs and is hiring attorneys, engineers and AI researchers. Buyers should watch which practice areas it adds first and whether it keeps flat, pre-quoted pricing as the work gets more complex.
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