AI agent startup Instinct has raised $1 billion at a $10 billion valuation, quadrupling its worth in about a month as investors pour money into personal AI assistants that act on a user’s behalf.

The Series C, announced September 28, drew backing from Sequoia Capital, Benchmark and Coatue. Founder Noah Shinn told the Wall Street Journal last month that the company had raised $250 million at a $2.5 billion valuation — the new round is a fourfold markup in roughly 30 days.

Founded in 2025, Instinct is building a personal agent that performs day-to-day tasks autonomously. Users communicate with it by text or phone call, asking it to plan trips, order groceries, book tickets or cancel subscriptions. A new concierge offering can even call businesses on a user’s behalf to make bookings.

The 23-year-old Shinn previously worked at Sierra, the AI customer-service startup run by Salesforce co-CEO Bret Taylor. Instinct says its privacy features include isolated sandboxes and short-lived local credentials, plus a new active detection system to catch subtle hallucinations before the agent acts.