Newport Beach-based Alliant Insurance Services Inc. has promoted Peter Carpenter to chief operating officer, a job he will start September 1.

Alliant is the largest insurance brokerage firm based in Orange County, with about $506 million in firmwide revenue last year. The company was acquired by New York-based investment firm Kohlberg Kravis Roberts & Co. late last year. The value of the deal was estimated to be more than $1.1 billion.

Carpenter currently serves as managing director of Alliant’s employee-benefits business in the Northeast and will continue to work from the firm’s New York office, for a "national balance" of the executive team, according to Alliant Chief Executive Tom Corbett, who is based in Newport Beach.

Carpenter will succeed Jerry Hall, who plans to retire after serving 25 years at Alliant, 17 of which as chief operating officer.

Carpenter joined Alliant in 2008 when it acquired Seattle-based ClearPoint LP, an employee-benefits consulting firm that he co-founded and was serving as chief executive.