The Big Four professional services firms, Deloitte, PwC, EY, and KPMG, underwent major operational and workforce changes as artificial intelligence became central to both internal work and client services in 2025 (31/12).

Covering the consulting industry throughout the year, Business Insider identified four key ways AI reshaped how the firms operate, hire, and deliver services.

AI Agents Moved Into Daily Use Across Firms

After years of investment, 2025 marked the point when AI tools became widely used across audit, tax, and consulting teams. Employees increasingly relied on chatbots and agentic AI systems, while clients were also given access to these technologies.

Deloitte launched Zora AI, developed with Nvidia, offering clients “intelligent digital workers” that can autonomously complete tasks. The firm also expanded generative AI features in its Omnia audit platform and partnered with Anthropic in October to deploy Claude AI to 470,000 employees worldwide.

EY introduced its agentic platform, EY.ai, granting 80,000 tax staff access to 150 AI agents. The firm said it advanced 1,000 AI agents into development or production in 2025 and plans to scale to 100,000 by 2028, while investing more than $1 billion annually in AI platforms and products.

PwC launched agent OS in March and deployed 25,000 intelligent agents across client operations, citing partnerships with Salesforce, CrewAI, and AWS as central to AI-led growth. KPMG followed with KPMG Workbench, built with Microsoft, and later launched KPMG Velocity for advisory work, adding to its existing audit and tax platforms.

The technology showed limitations when Deloitte agreed in October to partially refund the Australian government after errors were found in a report created in part using AI.

Entry-Level Hiring Slowed as AI Productivity Increased

AI adoption began reshaping staffing models, with firms shifting focus from manpower to value delivery. In August, internal PwC documents obtained by Business Insider showed plans to cut graduate hiring in the US by a third over the next three years, partly due to “the impact of AI.”

PwC said the decision reflected rapid technological change and historically low attrition. AI disruption also affected senior levels, as partners increasingly left the Big Four for midsize firms and startups offering faster-paced environments and opportunities linked to AI innovation.

Demand Rose for Technologists and AI Skills

While some roles declined, the firms increased hiring of technical talent. EY added 61,000 technologists since 2023, who now represent about 15% of its workforce.

PwC is “looking for hundreds and hundreds of engineers,” global chairman Mohamed Kande told the BBC in November. The firm also created an engineering career path to expand opportunities for technical staff.

Upskilling became a priority across firms. EY rolled out an internal AI tool in January to help employees understand how AI may change their roles, and nearly 100,000 employees earned a digital AI badge through new learning programs. At KPMG, AI training emphasized the importance of strong prompting to use the tools effectively.

Consulting Work and Business Models Began to Shift

AI is changing how consulting services are delivered, with firms moving away from short-term advisory projects toward long-term partnerships focused on building and maintaining AI tools.

“In 2025, organizations fit AI around their existing workflows,” Matt Wood, PwC’s global and US Chief Technology and Innovation Officer, told Business Insider. In 2026, PwC’s work will focus on “helping clients flip that model,” he said.

Raj Sharma, EY’s global managing partner for growth and innovation, said AI agents may require a “service-as-a-software” approach, where clients pay based on outcomes rather than hours worked.

The shift is also altering day-to-day roles. At PwC, new hires are expected to perform managerial tasks within three years by overseeing AI-led audit work, Jenn Kosar, AI assurance leader at PwC, said. KPMG echoed this approach, with juniors expected to manage teams of AI agents and play a larger role in strategic decisions.

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This article was created with AI assistance.

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