Anthropic likely to select EY as auditor amid Big Four conflicts

When three out of four major accounting firms are already doing business with you, your auditor shortlist gets very short. Anthropic, the AI safety company behind the Claude model, appears poised to tap EY as its external financial auditor, largely because the other Big Four firms have entangled themselves in commercial partnerships that would make independent auditing a regulatory headache.

Deloitte, PwC, and KPMG have all signed significant alliances with Anthropic, deploying Claude across their workforces and building new business units around the technology. EY, meanwhile, has been investing its AI chips elsewhere, building on Microsoft and Nvidia technology instead. That strategic divergence now gives EY something none of its rivals can offer Anthropic: a clean slate.

The conflict web

Auditor independence isn’t just a nice-to-have. It’s a foundational requirement under professional ethics standards, and it becomes especially critical when a company is eyeing a potential IPO. An auditor that also collects revenue from a client through consulting or technology partnerships creates exactly the kind of dual relationship that regulators frown upon.

Deloitte went deep first. In October 2025, the firm deployed Claude to more than 470,000 employees worldwide, making it the largest enterprise rollout for Anthropic’s technology.

PwC followed suit by expanding its Anthropic partnership in May 2026, launching a new CFO-focused business unit built around Claude.

KPMG rounded out the trio on May 19, 2026, signing a global alliance with Anthropic that gives its 276,000-plus employees access to Claude technology. The firm is using it specifically for private equity clients.

EY’s accidental advantage

In May 2026, EY unveiled a $1 billion initiative centered on Microsoft technology. The firm also launched what it calls the EY.ai Agentic Platform, which runs on Nvidia’s infrastructure rather than Anthropic’s Claude. By choosing Microsoft and Nvidia as its AI partners, EY inadvertently preserved the one thing its competitors sacrificed: the ability to audit Anthropic without a conflict of interest.

After the Enron scandal in the early 2000s, regulations tightened around what services an auditor could provide to its audit clients. The Sarbanes-Oxley Act drew bright lines between auditing and consulting relationships. But the current situation with Anthropic shows how AI partnerships have created a new category of entanglement that the original regulations didn’t quite anticipate.

When a firm rolls out a client’s AI product to hundreds of thousands of its own employees, it becomes both a customer and a commercial partner. That dual role creates financial dependencies that go well beyond traditional advisory work.

Why this matters beyond the audit

Anthropic’s auditor selection carries weight beyond accounting mechanics because it signals where the company sits on its journey toward public markets. Companies don’t typically stress about Big Four auditor independence unless they’re preparing financial statements that will face regulatory scrutiny, whether from SEC filings, investor due diligence, or IPO readiness processes.

The company has raised billions in funding from investors including Google and Salesforce. Having a clean, conflict-free auditor relationship from the start avoids the messy situation of having to switch auditors later, which tends to raise red flags with investors and regulators alike.

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