Consulting Firms Shift Toward Outcome-Based AI Fees
McKinsey now earns about 25% of its global fees from outcome-based pricing rather than billable hours, UK managing partner Michael Birshan said at a November 2025 briefing reported by Business Insider, as AI tools compress the analytical work consultants used to bill by the hour. McKinsey's internal assistant Lilli runs more than 500,000 prompts a month with consultants reporting up to 30% time savings, while Bain says AI- and tech-enabled work is roughly 30% of its revenue, projected to reach 50%, and BCG has told investors it expects AI work to reach about 40% of revenue by 2026. For AI and data teams, the shift means consulting engagements will increasingly tie payment to measurable outcomes, raising the bar on production-grade pipelines, monitoring, and clearly defined success metrics.
For ML engineers and data teams who work inside or alongside consulting engagements, outcome-based pricing reorders commercial incentives: contracts that tie pay to measurable business metrics require clearer success criteria, stronger telemetry, and production-grade pipelines rather than prototype notebooks.
What happened
Business Insider reported, per coverage by TheStreet, that McKinsey, Boston Consulting Group, and Bain are shifting client billing away from hourly and fixed-fee arrangements toward outcome- or risk-based pricing as AI tools cut the time needed for analytical work. Speaking at a November 2025 London briefing, McKinsey UK managing partner Michael Birshan said, "We're doing more performance-based arrangements with our clients," and the firm disclosed that about one quarter of its global fees now come from outcome-based pricing. McKinsey's global technology and AI leader Kate Smaje said at the same briefing that "many of the fundamentals of the professional services model are coming under challenge."
Industry context
McKinsey's internal AI assistant, Lilli, now runs more than 500,000 prompts a month, with consultants reporting up to 30% time savings on knowledge work, according to Hunt Scanlon Media. Bain has said AI- and tech-enabled revenue is roughly 30% of its business, with leadership projecting growth to 50%, and in May 2026 the firm announced an investment in the OpenAI-launched Deployment Company, extending a three-year Bain-OpenAI partnership focused on private-equity clients, according to Bain's own release. BCG CEO Christoph Schweizer has told investors the firm expects AI-tied work to reach roughly 40% of revenue by 2026, up from about 20% in 2024. Separately, Bloomberg has reported that around 150 former McKinsey, Bain, and BCG consultants have been contracted to help train AI models to perform entry-level consulting tasks.
For practitioners
Outcome-based deals typically require explicit success metrics, production-grade data pipelines, regression testing against baseline KPIs, and contractual clarity on data access and retraining cadence, shifting deliverables from prototype work to deployable services with defined service levels. Teams building or evaluating AI systems for consulting-style engagements should expect more scrutiny on causal measurement (isolating the model's contribution from other factors) rather than raw output volume.
What to watch
Whether outcome-based pricing becomes standard practice at the Big Three rather than a minority of engagements, whether Accenture and IBM, whose margins depend on the billable-hour leverage model, adopt comparable structures, and whether other knowledge-work sectors such as law and advertising follow the same shift.
Key Points
- 1McKinsey now earns about 25% of its global fees from outcome-based pricing as AI cuts the hours behind traditional billable-hour work.
- 2Bain and BCG report AI-tied revenue reaching roughly 30% and 40% of their businesses respectively, with both projecting further growth.
- 3Outcome-based contracts require production-grade pipelines, clear success metrics, and stronger data access terms rather than prototype deliverables.
Scoring Rationale
A well-corroborated shift in how major consulting firms price AI-accelerated work, confirmed through named executive quotes (McKinsey's Birshan and Smaje) and Bain's own investment announcement, with consistent figures across independent reporting. Notable for practitioners whose engagements will increasingly be scoped and measured against outcome metrics rather than hours.
Sources
Primary source and supporting public references used for this report.
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