The CAO-CFO alliance shaping finance at Brex

At most companies, the Chief Financial Officer remains the visible face of corporate finance. But as the expectations of the function expand, a quieter counterpart has moved into the spotlight: the Chief Accounting Officer (CAO).

For Erik Zhou, CAO at Brex, the role is not simply an extension of controllership. It is a recognition that accounting operations, technical interpretation and compliance are now too broad and too critical to sit beneath a single executive title.

“The entire finance function has been expected to rise significantly in the past 10 to 15 years,” he told The CFO at the Gartner CFO & Finance Executive Conference.

“We are no longer just the back office producing management packs. Finance is expected to work closely with every part of the business.”

From Numbers to Narrative

Zhou’s remit covers the full spectrum of accounting and financial operations: books and records, accounts payable, payroll, SEC reporting, and the technical accounting decisions that underpin timely and accurate statements. In a public company, that scope alone is formidable.

But at Brex, it is also the foundation of a close partnership with CFO Ben. “I put together all the materials, he takes those materials and interprets performance in the context of capital markets and comparable companies,” Zhou explained. “It is a simple way of saying I provide the accuracy, he provides the narrative.”

Their complementary backgrounds sharpen that division of labour. Zhou trained at a Big Four firm, spending 11 years in audit and technical accounting. Ben came from investment banking, focused on modelling, fundraising and investor communication. Together, Zhou argues, they represent the two halves of modern finance leadership: precision and storytelling.

Scaling Together

Brex’s growth trajectory has tested that partnership. The fintech recently secured a licence in EMEA, enabling it to issue cards and expand its services in the region.

Zhou describes the dual challenge: “For me, it is setting up the financial processes, determining funds flows, ensuring capital moves smoothly between the US and the UK entity. For Ben, it is managing investor expectations, asking how quickly this market will grow compared to the US.”

The work is not without friction. Regulatory applications demand patience, something Zhou admits can be in short supply in high-growth environments.

Cultural and operational differences add complexity. “The way we sell services in the US may be very different here,” he noted. “Expectations around corporate card use, billing, or approvals can vary. Understanding those nuances is as important as getting the books right.”

A Broader Finance Function

The bigger theme, however, is how roles themselves are shifting. Zhou sees finance as a business operations function, not just a reporting one. His team works with sales, marketing, R&D and general administration to understand the drivers behind the numbers.

“We are expected to collaborate, provide feedback, and make recommendations to improve performance,” he said.

That expectation flows down the hierarchy. Accountants entering the profession are no longer judged only on their ability to reconcile accounts.

“We are expected to understand where the numbers come from,” Zhou stressed. “That means building deeper relationships with the people who actually drive the business. The story starts long before a report lands in the general ledger.”

Managing Talent and Culture

As Brex scales internationally, Zhou believes the greatest challenge will not be technical but human. Processes can be set up and systems deployed, but aligning cultures across geographies is more delicate.

“Local financial systems are different, expectations of software are different, behaviours around spend are different,” he observed. “Managing that culture is crucial.”

The lesson for CFOs is clear: collaboration with a CAO is not optional. As finance becomes more embedded in operations, the scope of leadership is simply too wide for one individual.

“CFOs today are not just doing the numbers,” Zhou said. “They are telling the story behind them and making recommendations on where to take the company next. That requires partnership.”

Advice for CFOs

So what makes that partnership effective? Zhou’s answer is straightforward: relationships. “Finance leaders must develop a deeper appreciation of the story behind the numbers,” he argued. “That means understanding sales conversations, product development cycles, operational onboarding. Only then can the numbers carry meaning.”

In practice, that means spending time with business leaders, asking questions, and being willing to translate financial results back into operational realities. “It is not about inputting numbers,” Zhou concluded. “It is about connecting them to the people and processes that created them.”

For Brex, that approach has created a durable alliance at the top of finance: a CAO ensuring accuracy and compliance, and a CFO shaping the narrative for investors and markets. It is a model other companies may increasingly look to replicate as the demands on finance leadership continue to grow.

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