There’s a continuing trend of finance chiefs becoming chief operating officers (COOs), taking on dual COO roles, or even combining the CFO and COO positions. This shift is largely driven by the ever-expanding remit of the finance chief and the increasing needs of companies.

Over a 25-year career in strategic finance leadership, John Rettig has witnessed the CFO role transform in profound ways. Now serving as president and COO of the finance software company Bill, Rettig’s journey reflects the sweeping changes that have redefined what it means to be a finance leader.

Rettig, who joined Bill as CFO in 2014, began his COO role earlier this month to further accelerate company growth. He was succeeded as CFO by Rohini Jain, who joined Bill from PayPal, where she most recently served as CFO and SVP of Large Enterprise and Merchant Platforms.

I sat down with Rettig to get his perspective on his move from finance chief to COO.

“The impact and influence of the CFO have broadened dramatically compared to 25 years ago,” Rettig explained. Over the last decade, what he describes as the era of “CFO 2.0,” the job has shifted from simply reporting numbers to acting as a strategic advisor and true business partner to the CEO. “I’ve lived this transition myself, and my peers across tech and growth companies have seen the same thing,” he said. With the prevalence of AI, he believes we are now entering a new era—“CFO 3.0.” Finance chiefs must have a comprehensive understanding of technology deployed by the company, he said.

Rettig emphasized that the discipline and understanding required to communicate precisely—especially in the high-stakes context of a public company—are valuable assets when transitioning to a COO role.

“You really need to have visibility on execution, understand results, know where to dig deep, and gain a bottom-up understanding of how things work,” he said. This process can lead naturally to operational leadership responsibilities, including partnering with leaders across the business in the age of AI, he noted.

No ‘status quo’

AI is moving at “exponential speed,” even compared to just a year ago, Rettig said. “I think the exciting part about that is there’s no longer a status quo. AI is coming for everything.” This brings both tremendous opportunities and disruptive threats, he added.

For Rettig, success now requires an attitude of constant reinvention—leaning into emerging technology, experimenting boldly, and never being afraid to overhaul your business model before someone else does. “This is really powerful for the role of the CFO or COO, and the entire executive team,” he said.

Regarding Bill’s AI strategy, Rettig highlights two key areas: customer-facing products that automate complex financial processes and transformative internal improvements. “It’s not just about making work more efficient,” he explained, “it’s about using technology to eliminate work entirely.”

As president and COO, Rettig continues to focus on both short-term execution and long-term vision. During his tenure at Bill, which serves small and mid-sized businesses, the company has grown from 140 to 2,500 employees. His top priorities now include accelerating time-to-market, preparing the organization for future scale through investments in automation and operational efficiency, and making sure every resource is directed to its highest-value use.

A big part of his role will also be fostering company culture. “I’ve been with Bill for over 11 years now, which is a really long time in a Silicon Valley tech company,” Rettig said. The most important reason he came to Bill was the people. “And I’m still here for that same reason,” he said.

Sheryl Estrada
sheryl.estrada@fortune.com

Leaderboard

Justin Plouffe was promoted to CFO of global investment firm Carlyle (Nasdaq: CG), effective Jan. 1, 2026. Plouffe most recently served as deputy chief investment officer for Carlyle Global Credit. He has been with Carlyle for more than 18 years. Justin will succeed John Redett, who will continue serving as CFO through the end of the year.

Kristen Actis-Grande, EVP and CFO of MSC Industrial Supply Co. (NYSE: MSM), has decided to step down from her position, effective Aug.  8, to become CFO of a publicly traded company. Greg Clark, MSC's VP of finance and corporate controller, will assume the position of interim CFO following Actis-Grande's departure. Clark has held various finance positions with the Company since 2003. MSC will be conducting a search to identify a permanent CFO.

Big Deal

In the first half of 2025, the global IPO market saw 539 listings, raising $61.4 billion in capital—a 17% year-over-year increase in proceeds, according to EY's global IPO report. The firm noted that sustained IPO activity, despite significant policy uncertainty and market volatility, underscores the resilience and adaptability of well-prepared companies navigating today’s evolving capital markets. The U.S. led the way with 109 IPOs, marking its strongest first-half performance since the 2021 peak.

The global IPO market demonstrated resilience during the first half of 2025, and the outlook for the second half remains cautiously optimistic despite ongoing challenges, according to EY. 

Going deeper

Overheard

“At various points in my life, I’ve worked with people who I felt were better than me. You want that feeling a few times, trying to get yourself in a position where you’re working with people who you feel are kind of like stretching your abilities, is what helps you grow."

—Google CEO Sundar Pichai recently told Lex Fridman’s podcast. This approach has guided Sundar Pichai’s rise at Google, where he began as a product manager in 2004, Fortune reported. Within 10 years of working with cofounders Larry Page and Sergey Brin, he was appointed CEO in 2015.