Aon has appointed David DeBrunner as its new senior vice-president, global controller and chief accounting officer (CAO). 

In this capacity, DeBrunner will oversee the company’s accounting and financial reporting processes, reporting to Aon chief financial officer Edmund Reese.  

The appointment is effective on 15 September 2025.  

Reese said: “We are thrilled to welcome David to Aon. David’s leadership experience and deep expertise in accounting and financial services will be invaluable to both our shareholders and colleagues.” 

DeBrunner joins Aon with more than 30 years of financial services leadership, including expertise in strategic finance, complex accounting and regulatory reporting. 

Previously, he served as vice-president, CAO and controller at Ally Financial. 

His work at Ally included the unification of multiple accounting systems into a singular platform and the adoption of new methodologies for credit loss reserves.  

Before his time at Ally, DeBrunner held a similar position at Fifth Third Bancorp, where he played a key role in streamlining accounting operations through centralisation and the integration of technological solutions. 

DeBrunner will take over from Michael Neller, who has been Aon’s CAO and global controller since February 2018.  

Neller is transitioning to a strategic role focused on human resources and talent management within the company. 

Earlier this month, Aon strengthened its reinsurance division with key executive appointments. Alfonso Valera was named CEO of International for Reinsurance and Steve Hofmann was appointed CEO of Americas for Reinsurance.