Sierra is a US company that builds AI agents. It raised a $950 million Series E at a $15.8 billion valuation in May 2026, with annual recurring revenue having crossed $150 million within eight quarters of launch (Source: New Developments Log/2026-05-07.md). On July 23, 2026 it announced the acquisition of Takeoff, a 14-month-old, three-person startup building long-horizon agents that had reached nearly eight figures of annual recurring revenue; Sierra said the combined effort will operate under a new platform called Horizon (Source: sierra.ai; theinformation.com). The Information described the acquisition as a move to diversify Sierra's business (Source: theinformation.com).
Snapshot
Valuation
| Date | Value | Notes | Source |
|---|---|---|---|
| 2026-05-04 | $15.8B (Series E, $950M) | ARR crossed $150M in eight quarters | (Source: New Developments Log/2026-05-07.md) |
Relationships
- related: Agentic AI — long-horizon agents as an acquisition target category