Menlo Ventures report finds enterprises badly underestimated their AI bills

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 investing in AI rose only modestly, from 55% to 65%.

Where did the money come from? According to the report, 55% of the increased spending came from new budgets. Only 9% was shifted over from traditional SaaS tools to AI-native alternatives.

Agents are now the biggest customers

Autonomous AI agents now account for 80% of token usage on platforms built for model interaction, per the report.

Agent activity has grown 37 times since agents overtook human usage in early 2026.

Where the money went

Spending on AI applications reached approximately $77 billion, compared with $19 billion the year before.

Two categories dominated. Coding tools took in $34 billion, while productivity tools accounted for $25 billion. Together, coding and productivity made up 76% of that application spending.

At the infrastructure layer, the big frontier labs tightened their grip. Anthropic, OpenAI, and Google captured 69% of AI deployment spending in 2026, totaling $122.7 billion. In 2025, their share was 50%.

Within large language model API spend specifically, Anthropic led with 55%. OpenAI followed at 31%, and Google held 9%.

How the survey was done

The report draws on a survey of around 400 US decision-makers. It was conducted from September 8-26, 2026.