AI Capex Arms Race Revenue: $690B vs $63B Audit-Grade Floor - philippdubach.comSkip to main contentphilippdubach<br>Quantitative finance, AI, and the economics underneath.

Four widely-cited 2025 enterprise AI revenue figures span 40x ($37B Menlo, $100-135B vendor run-rate sum, $307B IDC, $1.478T Gartner); each is correct under its own perimeter, so the reconciliation is definitional rather than measurement error.<br>The audit-grade floor that defensibly underwrites $690B of 2026 hyperscaler capex is $63.2B narrow or $72.5B broad; looser numbers mix channel markup, third-party ARR claims, or full-retail device value into the same denominator.<br>Capex-to-revenue runs at 10.9x on the narrow audit-grade basis against the 1990s telecom peak of 3.5x; even after netting only AI-incremental capex, the ratio sits at 6.3-7.9x, worse than the closest historical analogue.<br>The Spread Index (audit-grade revenue over Gartner umbrella) opens at 4.28% narrow / 4.90% broad in May 2026; if it stays below 5% through Q4 2026, capex coverage cannot improve from disclosure alone and revenue itself must compound.

×Companion to the full research report, Reconciling Enterprise AI Revenue: A Methodological Crosswalk and Vendor-Level Census, 2025. The PDF carries the 68-vendor primary-source census, the six-tier disclosure framework, the per-step sourced deductions, and the netting of structural double-counts.<br>Three of the most widely cited enterprise AI revenue figures published in 2025 differ by 40x. A fourth, the vendor run-rate sum, sits between them. None is wrong. The defensible floor that underwrites $690B of hyperscaler capex sits at $63.2-72.5B.

Menlo Ventures put US enterprise generative AI spending at $37B for 2025 in its December 2025 report. The bottom-up sum of disclosed vendor run-rates lands at $100-135B worldwide. IDC sizes the 2025 AI Solutions market at $307B. Gartner forecasts $1.478T for total worldwide AI spending in 2025. The trade press cites all four as &ldquo;the AI market.&rdquo; Menlo is not the cautious one and Gartner is not the aggressive one. Each figure is methodologically explicit about what it counts, and each is correct under its own perimeter. They just widely disagree about what enterprise AI revenue is, not how to count it.<br>Why does this even matter? Hyperscaler 2026 capex guidance now approaches $690B, financed in part by roughly $1.5T of AI-related debt issuance over the coming cycle per sell-side estimates, with JPMorgan, Apollo, Blackstone, and KKR structuring the paper. Against the $63.2B narrow audit-grade revenue floor, capex coverage is 9.2%. The 1990s telecom buildout peaked at roughly 28% coverage (the inverse of 3.5x capex-to-revenue).<br>Four numbers<br>Menlo Ventures: $37B. A buyer-side survey of 495 US enterprise IT decision-makers, fielded November 7-25, 2025 in partnership with an independent research firm, asking respondents to identify the 2025 budget line items they tag as generative AI spend. Three explicit scope restrictions: US only, GenAI only, enterprise only. The narrowest published figure.<br>Vendor run-rate sum: $100-135B. Built bottom-up from a 68-vendor primary-source census (42 public, 26 private), graded against a six-tier disclosure framework. The lower bound applies maximal resale netting and an ARR-to-recognized-revenue haircut; the upper bound is the net-of-silicon, gross-of-resale presentation; midpoint $123B fully-net. The vendor census makes every dollar reproducible.<br>IDC: $307B. Worldwide AI Solutions, sized by the IDC Worldwide AI Spending Guide from vendor share data and channel surveys. Hardware, services, and software where IDC tracks them as bundled into enterprise AI solutions. No consumer device hardware. Mixes vendor recognition with buyer spend in a single figure.<br>Gartner: $1.478T. Worldwide AI spending across five buckets per the September 17, 2025 release: AI-enabled devices ($389B), AI services ($283B), AI-optimized servers ($268B), AI software ($298B), and an &ldquo;other&rdquo; category ($242B). Counts the full retail value of any product sold with an AI feature. Gartner&rsquo;s own analyst John Lovelock conceded the device layer is &ldquo;largely sold along with the product and not specifically selected&rdquo; by buyers.<br>Each figure answers a different question. Menlo captures what enterprise buyers consciously buy. The vendor sum captures what suppliers recognize. IDC bundles in services and integration. Gartner counts every product sold with an AI feature inside it.

×Waterfall: from $1.478T to $37B<br>Each step below applies the next forecaster&rsquo;s published perimeter to the prior figure. Disagree with any step and you can substitute your own assumption and rebuild the bridge.<br>Step 1: $1.478T to $307B. Strip the umbrella. Subtract Gartner&rsquo;s $389B of AI-enabled devices, where a $1,200 phone with an AI camera filter contributes $1,200 to Gartner and zero to IDC. Subtract roughly $200B of broad AI services Gartner counts but IDC excludes, $268B of...