Alliant Insurance Services: insurance broker profile

Overview

Alliant Insurance Services is a privately held specialty insurance broker, headquartered in Irvine, California according to the dateline on its recent press releases. In Business Insurance's ranking of the world's largest brokers, published June 26, 2026, Alliant ranked No. 6, down one place, with 2025 brokerage revenue of $5.72 billion, up 14.4% after growth of nearly 30% in the prior year. The ranking does not give a headcount, and we did not find a current company-published figure. Greg Zimmer is chief executive.

Business Insurance calls Alliant the largest private-equity-backed brokerage and said S&P Global Ratings put its 2025 organic growth at 8.6%. S&P upgraded Alliant Holdings LP's issuer credit rating from "B" to "B+" in May 2026, per the same article.

History

Alliant says it was founded in 1925 in San Diego, California, and celebrated its 100th anniversary at the 2024 and 2025 RIMS RISKWORLD conferences. Orange County Business Journal reporting says its Newport Beach office opened in 1977. Alliant first entered Business Insurance's top 10 brokers in 2022, according to the 2026 profile.

On ownership, Business Insurance reported in 2015 that Stone Point Capital would take a stake in Alliant, replacing Kohlberg Kravis Roberts as its largest institutional investor, with management and producers remaining significant shareholders. A 2019 investment by the Public Sector Pension Investment Board followed, with Stone Point described as remaining the largest institutional shareholder and producers and management continuing to own the majority. We did not find a 2025 or 2026 source that confirms the current mix, so treat that history as dated. Alliant's own site refers to an "employee-ownership culture."

Services

Alliant's website groups its work into risk management (with industry practices such as agribusiness, construction, cyber and healthcare, and risk solutions such as captive insurance, claims, surety and trade), employee benefits (consulting, compliance, pharmacy and voluntary benefits), reinsurance, underwriting solutions, and retirement and wealth. Business Insurance named construction insurance, commercial auto liability and reinsurance as the main drivers of 2025 growth. Reinsurance grew more than 50%, and the firm is now, in the article's words, essentially a facultative-only shop. Employee benefits grew more than 12%. Alliant's underwriting solutions include programs and managing general agent work; for background see Managing general agents (MGAs): what they are and what they mean for buyers and program business: niche insurance through program administrators.

Who it serves

Alliant works mainly with commercial clients that have specialized exposures: contractors and developers, public entities, transportation fleets and agribusiness appear among the industry practices on its site. Its offices are in the U.S. and Canada. For a contractor deciding between a specialty broker and a local agency, how to choose a commercial insurance broker and independent agent, broker, captive agent or direct? explain how to compare them, and Writing a broker RFP for a commercial insurance program covers putting the question to market.

How it is paid

We did not find a statement on Alliant's website or in the Business Insurance profile that explains how Alliant is compensated, and as a private firm it publishes no audited financial statements. Brokers generally earn commissions from insurers, negotiated client fees, or both, and some also receive supplemental or contingent payments from insurers. Alliant's underwriting solutions and reinsurance units may also earn revenue in other ways, such as program or facultative fees; we could not verify the arrangements. Ask Alliant for its compensation on your account in writing, including any payment from an insurer. how commercial insurance brokers get paid covers the models.

Recent deals

• Acquisitions: Business Insurance reported no material acquisitions by Alliant in 2025, only "a handful" of small tuck-in deals, and a strong deal pipeline for the rest of 2026. Alliant's emphasis is organic growth and recruiting talent from competitors.
• Howden litigation: the same article says Alliant sued Howden in 2026 after Howden hired several of its staff. We have not verified the claims or outcome.
• Credit rating: S&P raised Alliant Holdings LP to B+ in May 2026.
• Leadership: Peter Arkley was promoted to president of the national retail brokerage, a new role, and Michael J. Cusack, who previously led Alliant Specialty, succeeded him as president of the property and casualty division.

Alliant's growth path contrasts with acquisitive peers; see private equity and the consolidation of insurance brokers.

Strengths and weaknesses

Alliant's growth from construction, auto liability and facultative reinsurance reflects a firm that has taken market share through specialty expertise and hiring. Management told Business Insurance it expects future growth from construction, reinsurance and benefits, and sees artificial intelligence as an efficiency tool that will not displace brokers on complex commercial risks.

• Strengths: specialty depth in construction, auto liability and facultative reinsurance; strong 2025 revenue growth; staff recruiting momentum.
• Weaknesses: speculative-grade credit rating (B+ from S&P); litigation with a competitor over staff moves; limited public disclosure of ownership and compensation.

How to contact Alliant Insurance Services