Legal AI Consumption Pricing: 47% YoY Spend Increase — And 62% Over Budget

The Legal Stack's "Legal AI Compute Cost Shift Report 2026" found that among in-house teams fully transitioned to consumption-based AI pricing from at least one major vendor, average annual AI spend increased 47.3% year-over-year, compared with 12.1% for teams still on legacy seat licenses. The median increase was 31.8%. Critically, 62% of respondents who exceeded budget reported that their actual AI spend increase exceeded their projection at contract renewal — the average overage was 28.4% above forecast. For law firm BD teams, this data has two implications. First, in-house legal budgets are under new pressure from AI consumption costs that are harder to forecast than traditional software licenses. CFO scrutiny of the legal department's AI spend is intensifying at the same time that outside counsel rates are rising. Second, in-house teams that are over-budget on AI are more likely to implement tighter outside counsel controls — panel reviews, rate freezes, volume reallocations — as the mechanism for offsetting AI overspend. BD and pricing teams at outside counsel firms should anticipate these budget pressures in client conversations through year-end and in 2027 fee discussions.