Menlo Ventures report finds enterprises badly underestimated their AI bills

A small group of heavy AI agent users pushed corporate AI spending far past what companies had budgeted for in 2026 Corporate finance teams planned for AI spending to roughly double this year. It did a lot more than that. Menlo Ventures released its 2026 State of Enterprise AI report on November 3, 2026. The findings suggest enterprises didn’t just miss their AI budget targets. They missed them by a mile. A summary of the findings shared on X said a small group of heavy AI agent users drove enterprise AI spending to 4.7 times 2025 levels. Companies had planned for 1.9 times. The numbers behind the overrun The report’s top-line deployment figure is striking. Enterprise AI deployment spending reached $176.8 billion by September 2026, up from $33 billion in 2025. That works out to a 5.4x jump. It also marks an acceleration, since the prior year’s growth rate was 3.9x. Enterprises had forecast growth in the range of 1.9-2x. Instead, they ended up spending about 2.5x their planned budgets on AI. For the heaviest users, particularly those running autonomous AI agents, the gap between plan and reality was the widest. What’s notable is who did the spending. The share of enterprises investi...