The Big Four accountancy firms — Deloitte, PwC, EY, and KPMG — are encountering significant cultural and structural obstacles in adopting artificial intelligence at scale, according to former EY UK boss Hywel Ball.
In comments reported by the Financial Times, Ball said that while the Big Four are investing heavily in AI, their size and complexity present inherent challenges to implementation. “There is a patch in the middle” of the market, he said, “between being nimble and having enough critical mass to give you the momentum,” where mid-sized firms have an opening to innovate faster and more freely.
“If you’re really big there are lots of challenges about driving that extent of cultural change,” said Ball, who retired from EY earlier this year after nearly four decades at the firm. “The Big Four… have the resources and investment to do it, but they’ll have their own challenges for adoption, because they’re so big.” He emphasized that changing entrenched behaviors across thousands of employees and business units is a major hurdle.
Ball made the comments as he announced new roles at two boutique AI firms. He will become non-executive chair and director at UK-based start-up IntellixCore, founded by former PwC partners Sultan Mahmood and Mike Greig, which offers AI transformation services to professional services firms and private equity portfolio companies. Ball will also join the board of Quantum Rise, a Chicago-based, private equity-backed AI consultancy.
Ball’s transition reflects a broader trend of senior figures in traditional firms moving into agile, AI-native consultancies — businesses unburdened by legacy systems or bureaucracy. These nimble players are increasingly positioning themselves to disrupt conventional advisory models.
On the future of jobs, Ball acknowledged that AI would bring about “some job losses”, but predicted that employment would “quickly rebound” as firms adapt. “You’ll go through a curve [of job losses and new hires] as people get to understand this new technology and how it can be used,” he said.
Rather than trying to compete directly with global AI leaders such as OpenAI or Meta, Ball argued that the UK should focus on “AI adoption” across sectors. This includes professional services, where Ball sees consultancies as central to the broader transformation — and therefore under pressure to lead by example.
“Physician, heal thyself,” he remarked. “If you’re an accounting, consulting or professional services firm and you’re not doing the AI adoption yourself, it’s pretty tricky to go and tell someone else that this is really important.”
IntellixCore has already made moves to scale its influence. Last month, it announced a partnership with RSM, the UK’s seventh-largest accountancy firm. Ball said the collaboration would “re-architect how a professional services firm actually operates.”
His message underscores a growing industry realization: while resources and scale are critical, agility and cultural alignment may be the defining factors in successful AI adoption. As professional services face growing demand for AI expertise, the pressure is now on the incumbents to prove they can change from within.
