HOW BIG FOUR TECHNOLOGY INVESTMENTS IN AUDIT WILL SPILL OVER INTO THE LEGAL SECTOR
In a recent article on how the Big Four are deploying artificial intelligence in their audit practices, several themes emerge that carry direct implications for the legal sector. Law firms can no longer ignore these developments, given the Big Four’s capacity to invest “hundreds of millions” into new technologies and then use them across multiple lines of service.
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Scale of Investment and the Drive to Deploy Technology
One striking point is the scale of AI investment by the Big Four. While these tools are showcased in audit, the technology will not remain isolated there. Once the Big Four have built advanced platforms for data analysis, pattern recognition and anomaly detection, they have every incentive to redeploy these tools across other service areas, including legal.
For law firms—particularly those without similarly deep pockets—this is a wake-up call. Clients, hungry for efficiency and integration, increasingly value providers who can seamlessly connect different services. As the Big Four continue to refine their technology, legal teams that fail to modernise risk being left behind.
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Competitive Advantage Through an Integrated Approach
One of the key competitive advantages the Big Four hold is their ability to spot potential legal or regulatory issues in real time while conducting audits or advisory work. Having immediate access to a client’s data means they can swiftly identify challenges and then bring in their in-house legal expertise to address these problems.
Law firms typically engage once a specific legal matter surfaces. However, the Big Four’s integrated approach—supported by AI that can search and analyse mountains of data instantly—lets them bundle audit, regulatory, compliance and legal services into one cohesive package. This erodes the traditional boundaries between financial, compliance and legal work.
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Deep Client Integration and Co-Developed Technology
Thanks to their broad reach and strong balance sheets, the Big Four can co-develop AI and other digital tools with their clients at pace. Rather than waiting for annual software releases, these firms are moving to quarterly and even more frequent updates. Clients are increasingly drawn to this collaborative, rapid innovation cycle.
In the legal sector, it is less common for firms to build bespoke solutions with clients. Instead, many law firms still focus on traditional, case-by-case service. To stay relevant, however, forward-thinking firms should look for ways to co-create technology solutions with their clients, delivering a service model that is dynamic, tech-savvy and proactive.
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Rapid Roll-Out and “Buying” Market Share
The Big Four’s sizeable cash reserves allow them to invest in technology and move quickly to gain market share. They can even undercut traditional providers by discounting in targeted areas—particularly useful where “routine” legal work is concerned. Although the article highlights that audit fees remain high, the larger point is that these global professional services networks can afford to be strategic about pricing and bundle different services to secure new clients.
For law firms, the threat is clear: if Big Four firms decide to claim more of the routine legal market—data-heavy work such as diligence, compliance or investigations—they could then push further up the complexity chain. Many firms rely heavily on routine work for steady income, which subsidises occasional big-ticket cases. Losing that base could destabilise a law firm’s entire practice.
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Profit Pressures Driving Ambition
As the audit landscape evolves, the Big Four face their own challenges—rising regulatory costs, increased oversight and new technologies all apply downward pressure on traditional revenues. In response, they are motivated to secure new revenue streams in ancillary areas, including legal services. For law firms to assume that only “bet-the-farm” matters will remain exclusively theirs is risky. The Big Four are well placed to move, fast, into higher-value legal segments once they have established themselves in routine or mid-level work.
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Moving Beyond the “Complex Work” Fallacy
It is tempting for law firms to believe clients will always want them for significant litigation, major mergers or other high-stakes matters. Yet most work in a typical legal practice is neither “bet-the-farm” nor privileged to a level that only law firms can handle it. AI is increasingly capable of dealing with matters traditionally viewed as intricate, and the boundary between “routine” and “complex” is shifting. Firms that focus solely on the higher end of the market may discover too late that technology has transformed what was once considered complex into something more commoditised.
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Additional Considerations for Law Firms
- Talent and Recruitment: If the Big Four can offer technology-rich, multi-disciplinary career paths, they may attract top-tier talent away from law firms.
- Data Ownership and Trust: In the legal sector, confidentiality and data security are paramount. Yet the Big Four have deep pockets to invest in cybersecurity and data infrastructure, ensuring client data is protected.
- Regulatory Rules: While rules limiting how non-lawyers can own or run law firms still apply in many jurisdictions, ongoing changes could open more doors for the Big Four’s expansion.
- Global vs Local: The Big Four have well-integrated global networks, while law firms often rely on local partnerships. Clients seeking consistency across borders may favour providers who operate on a unified global platform.
How Law Firms Should Respond
The Big Four’s success in deploying AI for auditing signals a major shift. With powerful, integrated tech stacks, large balance sheets and integrated service offerings, they are well positioned to challenge law firms—particularly on routine legal work, but also in more complex advisory areas over time.
Law firms that wish to remain competitive must:
- Invest significantly in integrated technology, analytics and process automation. An integrated AI Platform creates more value than a single LLM or Gen AI bridge.
- Adopt a more client-centric approach, co-creating platforms or solutions.
- Avoid complacency by relying solely on “complex” work.
- Strengthen talent pipelines and cybersecurity measures to match Big Four standards.
Ignoring the Big Four’s advancement, or assuming that their technology stays in the audit space, would be a serious mistake. As the audit industry’s rapid evolution shows, technology is transforming professional services. Law firms that respond swiftly and decisively, will have the best chance of maintaining and growing their market share in this new era.