AI agent startup Instinct hits $10B valuation after $1B Series C — one month after its last raise

Roughly one month after closing a $250 million round that valued it at $2.5 billion, AI agent startup Instinct has raised another $1 billion — this time at a $10 billion valuation — from Sequoia Capital, Benchmark Capital, and Coatue. The Series C, confirmed in a press release on Monday, caps one of the fastest valuation climbs the AI industry has recorded: the company was worth roughly $50 million in the spring.

That trajectory — from $50 million to $10 billion in five months — is being driven by a product that is deliberately simple to use. Instinct has no app. Users text or call it, and the agent carries out tasks using its own phone number and computer, operating software the way a human assistant would. It can book travel and restaurant reservations, order groceries, cancel subscriptions, negotiate bills, conduct research, and make phone calls on a user's behalf through a feature called 'concierge.' A 'trusted person network,' opened to all users on September 14, lets one person's Instinct agent coordinate plans directly with the agents of their friends and family — a feature that had already logged more than 300,000 coordinations when opened, according to officechai.com.

The company behind it, Spear Street Technology, Inc., is registered in California and has just 14 employees — a figure that puts its implied valuation at more than $700 million per head, according to officechai.com. It is still invite-only, has crossed 100,000 users, and has at times told users it is running at capacity. Founder Noah Shinn has said he has no intention of charging users, keeping the product free for now and leaving the question of how it will eventually make money unanswered; one option that has been discussed is advertising.

We’re building Instinct to be the best personal agent that can handle the deeply personal nuances of everyday life. This funding helps us bring Instinct to more people and continue building the future of personal AI. It’s an exciting, creative time, and we’re just getting started.— Noah Shinn, Founder and CEO, Instinct

Shinn, 23, declined to give interviews alongside the fundraising announcement. Academic and professional experience that mirrors the product he built: Shinn studied at Northeastern University, pursued machine learning and programming-language research at both Northeastern and MIT, and left school in 2023 without completing his degree. In 2023, he was listed as lead author on Reflexion, a paper delivered at NeurIPS demonstrating that language agents can strengthen their performance by reflecting on past failures in natural language and retaining those reflections as memory — an approach that reportedly achieved 91% pass@1 on the HumanEval coding benchmark, surpassing the 80% figure reported for GPT-4 at the time, according to officechai.com. Before founding Instinct, he signed on at Sierra — the enterprise agent company started by Bret Taylor and Clay Bavor — as a research scientist and one of its first hires, a role in which he helped create τ-bench, a benchmark designed to evaluate how reliably agents handle multi-step tasks.

Instinct's full financing history has unfolded in months, not years. An early round at roughly $50 million was backed by Conviction and Greenoaks. In early August, Kleiner Perkins took the lead on a $75 million Series A that valued the company at roughly $500 million. Index Ventures and Benchmark co-led the $250 million Series B at $2.5 billion on August 26. The new $1 billion Series C brings total funding to more than $1.3 billion, according to officechai.com.

The raise arrives at a moment of intensifying competition. On September 8, Meta introduced its own personal agent, Muse, which has since secured commerce partnerships with Shopify, PayPal, Instacart, and Expedia, according to officechai.com. Muse can monitor and summarize Instagram DMs, Facebook Groups, and Marketplace listings, and has reached the top of U.S. app stores with millions of downloads, according to TechCrunch. Instinct, which operates entirely over SMS and has no mobile app, has not disclosed user numbers. According to officechai.com, there are indications that OpenAI is also working on a persistent, always-available assistant.

The deeper challenge for Instinct is trust. Because the agent requires broad access to a user's email, calendar, messaging apps, and other accounts to function, its terms of service have drawn scrutiny from privacy researchers. TechCrunch reported security and privacy concerns in August, and Instinct's initial privacy policy was described as particularly overreaching before being updated. When a user recently reported that Instinct had described a financial document belonging to someone else, Shinn said no user data had been shared and that the model had invented the details; he added that the company had put in place a system to catch hallucinations across all of the platform's output, according to officechai.com. The company also says it incorporated sandboxing, short-lived credentials, and identity-signed tool execution into the product from the outset.

For now, investors are betting that a focused product and a fast start can hold ground against much larger rivals. Whether Instinct can convert that bet into a sustainable business — without an app, without disclosed user metrics, and without a clear revenue model — is the question its next chapter will have to answer.

Why it matters — Instinct's raise tests whether a tiny, app-free startup can build and hold a mass consumer AI market before Meta, OpenAI, and other trillion-dollar players fully arrive — while unresolved questions about privacy, trust, and revenue model follow every new dollar in.

Reported by techcrunch.com, bloomberg.com, reuters.com, officechai.com