The Big Four professional services firms are grappling with AI on two fronts — they must both implement the new technology internally and help their clients do the same.
They’re client zero when it comes to how companies and employees are adapting to the AI future.
I’ve been covering the consulting industry for Business Insider all year, including interviewing execs, landing scoops, and visiting consulting giants’ campuses and headquarters. Here are my four key takeaways about how the Big Four approached AI in 2025.
1. The year of the AI agent
The Big Four have invested heavily in automation and AI for years, but 2025 was the year those tools went mainstream.
Employees across audit, tax, and consulting now routinely use chatbots and agentic AI systems, and clients are increasingly given access as well.
Deloitte rolled out Zora AI, an agentic platform built with Nvidia, which offers clients “intelligent digital workers” capable of autonomously completing tasks. The firm also expanded generative AI features in Omnia, its cloud-based audit and assurance platform, and struck a deal with Anthropic in October to deploy Claude AI to its 470,000 employees worldwide.
EY launched its own agentic platform, EY.ai, granting 80,000 tax staff access to 150 AI agents for tasks such as data collection, document review, and tax compliance. EY told Business Insider it has advanced 1,000 AI agents into development or production in 2025, with plans to scale to 100,000 by 2028, and is investing more than $1 billion annually in AI platforms and products.
PwC introduced its agentic platform, agent OS, in March and has since deployed 25,000 intelligent agents across client operations. A PwC spokesperson told Business Insider that partnerships with companies like Salesforce, CrewAI, and AWS were central to how PWC drove AI-led growth in 2025.
KPMG followed in June with KPMG Workbench, an agentic AI platform developed with Microsoft that connects 50 AI agents and chatbots, with nearly 1,000 more in development. In October, it launched KPMG Velocity for advisory work, adding to Clara, its audit platform used by more than 95,000 auditors globally, and the Digital Gateway for tax.
The tools aren’t foolproof. In October, Deloitte agreed to partially refund the Australian government after errors were discovered in a report that was created in part using AI.
2. A hiring slowdown at the entry level
Across industries, the big question is what AI will mean for human jobs. In consulting, the technology is already accelerating a shift in focus from manpower to value.
In August, Business Insider obtained part of an internal presentation showing that PwC US planned to cut graduate hiring by a third over the next three years. A bullet point on the presentation slide said leadership’s decision to slow down associate-level hiring was related in part to “the impact of AI.”
The company said the reductions reflected “the rapid pace of technological change is reshaping how we work” and “historically low” attrition.
AI disruption is also impacting those at the upper levels of the Big Four. Partners, the most senior rank inside the firms, are increasingly leaving the Big Four for midsize organizations and startups. Several leaders Business Insider spoke to cited a faster pace, better promotion opportunities, and the chance to participate in the next wave of AI innovation as reasons for leaving.
3. The rise of the technologist
There is one talent group that the Big Four are in the market for: technologists. EY has added 61,000 technologists to its ranks since 2023, according to its latest annual report. They now make up around 15% of its total workforce.
PwC is “looking for hundreds and hundreds of engineers,” Mohamed Kande, the firm’s global chairman, told the BBC in November. The firm has created an engineering career path to “elevate engineering excellence” across the firm and expand opportunities for technical talent, PwC told Business Insider.
Upskilling has also become a top priority for the Big Four.
In January, EY rolled out an AI tool to its employees that helps them identify how their jobs will change… because of AI. The aim is to help them work out how they can better use the technology in their current job and adapt for the future.
Nearly 100,000 EY employees — roughly a quarter of the workforce — have also earned a digital “AI badge” for completing one of the firm’s new AI learning programs.
But as Business Insider learned while sitting in on a KPMG’s AI training for tax interns, in professional services, some of AI’s most effective uses hinge on strong prompting.
4. The work is changing
The work that consultants and accountants do is changing. Straight advisory projects are being replaced by long-term partnerships where consultants build, implement, and maintain tools for companies.
In 2025, organizations fit AI around their existing workflows, Matt Wood, PwC’s global and US Chief Technology and Innovation Officer, told Business Insider. But in 2026, the work PwC will do is about “helping clients flip that model,” and designing processes with AI in mind from the outset, Wood said.
Raj Sharma, EY’s global managing partner for growth and innovation, told Business Insider in January that the power of AI agents is forcing his firm to reconsider its commercial model. Instead of charging clients based on the hours and resources EY might spend on a project, Sharma said AI agents may call for a “service-as-a-software” approach where clients pay based on outcome.
The shift in services means that what consultants do on a day-to-day basis is also evolving, with junior work expected to be disrupted first.
At PwC, new hires will be doing the roles that managers are doing within three years, because they will be overseeing AI performing routine, repetitive audit tasks, Jenn Kosar, AI assurance leader at PwC, told Business Insider in August.
KPMG is also prepping its junior consultants for career acceleration.
“We want juniors to become managers of agents,” Niale Cleobury, KPMG’s global AI workforce lead, told Business Insider in an interview in November. They’ll be managing teams of AI agents and play a greater role in strategy decisions, he said.
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