The world’s largest professional services firms—Deloitte, EY, KPMG, and PwC—collectively known as the Big Four, are locked in an intense competition to demonstrate AI leadership as they navigate a challenging business environment. With a combined 1.5 million employees globally and billions in annual revenue, these consulting giants are investing heavily in AI capabilities both for internal operations and client services.
Financial Performance Overview: After experiencing a pandemic-era boom followed by a sharp slowdown, the Big Four saw modest growth return in their latest financial years. Deloitte led with $70.5 billion in revenue and 4.8% growth, expanding its workforce by 10,000 employees to 470,000 total. PwC recorded the slowest growth at 2.7% with $56.9 billion in revenue, and was the only firm to reduce headcount, cutting 5,600 positions to 364,000 employees—reversing previous expansion goals. EY achieved 4% growth with $53.2 billion in revenue and expanded its workforce by 3.4% to 406,206 employees. KPMG, the smallest of the four, posted 5.1% growth with $39.8 billion in revenue and 276,030 employees.
AI-Driven Transformation: The professional services industry faces significant exposure to AI-driven disruption, fundamentally changing the nature of consulting work and required talent. EY reported particularly strong AI-related service demand, with a 30% revenue increase from work including enterprise-wide AI transformations and AI governance frameworks. The firm’s consulting business rebounded with 5.2% growth after stagnation the previous year, driven largely by AI initiatives.
Strategic Positioning: All four firms are racing to prove they can effectively deploy AI internally while guiding clients through similar transitions. This dual challenge represents both an existential threat and massive opportunity. The firms are restructuring operations to accommodate AI capabilities—Deloitte consolidated from five to four business lines, while KPMG became the first Big Four firm to establish a US legal division in February 2025. PwC has implemented innovative approaches like hosting “promoting parties” to increase employee comfort with AI tools, recognizing that cultural adoption is as critical as technical implementation.
Key Quotes
The professional services industry is also highly exposed to AI-driven transformation. AI is rapidly changing the type of work that consulting firms offer their clients and the talent they require to carry it out.
This observation from the article captures the existential challenge facing the Big Four, highlighting how AI is simultaneously disrupting their traditional service offerings while creating new business opportunities that require fundamentally different skill sets.
solid performance in a challenging economic climate
PwC characterized its 2.7% growth and workforce reduction with this statement, reflecting the broader tension between modest economic recovery and the need to invest heavily in AI capabilities while managing costs—a balancing act all four firms are navigating.
Our Take
The Big Four’s AI race represents a fascinating case study in how established industry leaders respond to disruptive technology. EY’s 30% AI revenue growth stands out as evidence that clients are willing to pay premium rates for AI expertise, creating a powerful incentive for aggressive investment. However, PwC’s workforce reduction suggests AI may be enabling these firms to deliver more value with fewer people—a trend that could accelerate across professional services. The real test will be whether these firms can maintain their advisory credibility while simultaneously undergoing their own AI transformations. Their ability to “eat their own dog food” by successfully implementing AI internally will determine whether clients trust them as guides through similar journeys. The billions being invested signal these firms recognize AI as an existential imperative, not merely an incremental improvement. This competitive dynamic will likely produce valuable lessons about enterprise AI adoption that extend far beyond consulting.
Why This Matters
This story reveals how AI is fundamentally reshaping the consulting industry at its highest levels, with implications extending far beyond the Big Four themselves. These firms collectively advise thousands of Fortune 500 companies and government agencies worldwide, making their AI strategies a bellwether for broader corporate transformation. EY’s 30% revenue surge in AI-related services demonstrates that enterprise AI adoption is accelerating despite economic headwinds, signaling a structural shift rather than a passing trend.
The divergent workforce strategies—with PwC cutting 5,600 jobs while competitors expand—illustrate AI’s disruptive impact on professional services employment. This foreshadows similar dynamics across knowledge work sectors as AI automates routine tasks while creating demand for new specialized roles. The billions in AI investments by these firms represent a critical test case for whether traditional consulting models can successfully pivot to AI-driven service delivery. Their success or failure will influence how thousands of other professional services firms approach their own AI transformations, affecting millions of workers globally and shaping the future of white-collar work.
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Source: https://www.businessinsider.com/big-four-earnings-compared-ey-deloitte-pwc-kpmg-2025-12