Insurance / Brokerage · Deep dive

Alliant Insurance Services

The specialty brokerage that grows by hiring your best team on a Tuesday morning — a 1925 San Diego agency turned $5.7B-revenue, majority-employee-owned lift-out machine that has out-litigated Aon twice, outrun four private equity owners, and climbed to No. 4 in America without ever going public.

well positioned

Alliant has industrialized the one act rivals cannot defend against — buying their best producer teams with equity that has compounded through four sponsor recaps — and courts have twice refused to shut the machine down, so the model keeps converting competitors' payrolls into 20%-a-year growth.

My take ★★ Very interesting ★ Interesting − Maybe ✗ Not interesting

Snapshot

Alliant Insurance Services is the fourth-largest broker of US business — more than $5.7B of revenue and roughly $55B of premium placed in 2025 — and it got there without an IPO and largely without the roll-up acquisition sprees that built its peers. Its core growth engine is the producer “lift-out”: hiring entire specialty teams from rivals, guaranteeing their compensation, handing them equity in a majority-employee-owned company, and litigating the resulting non-compete lawsuits as a routine cost of doing business. Stone Point Capital has been the lead institutional sponsor since 2015, with Canada’s PSP Investments alongside since 2019. The model has survived four private equity owners, two jury trials, and the fury of every large rival; the question is whether bought loyalty and recap-driven equity keep compounding as P&C pricing softens.

Founding story

The founding asset is the Robert F. Driver Co., a San Diego agency organized in 1925 under a producer-owned partnership model — equity allocated by book of business, top producers controlling the votes. That structure, not any product, is the DNA that still runs the firm. Tom Corbett joined Driver as a producer in 1977 and built its public-entity practice — insurance pools for municipalities, schools, and special districts — into one of the largest programs of its kind in the country, then took over the company itself, running it as chairman and CEO for more than three decades. In June 2001 the business reorganized when Alliant Resources Group acquired the Driver company (roughly $56M of revenue and $500M of premium in 2000, per Insurance Journal), creating the modern platform.

Then came the private equity relay. Lindsay Goldberg backed the firm in the mid-2000s; Blackstone bought control in 2007 for a reported ~$1.1B, partnering with management and employees; KKR bought it from Blackstone in November 2012, with employees owning about 45% going in and rolling a substantial portion; Stone Point Capital acquired roughly half from KKR in June 2015; PSP Investments joined in 2019. At every hop, Corbett’s condition held: management and producers keep the majority. Greg Zimmer — CFO from 1998, president from 2007, architect of the M&A program — became CEO on April 1, 2024, with Corbett staying on as executive chairman.

How it works

A broker’s revenue walks out the door every night in the heads of its producers, and Alliant has industrialized that fact. The mechanics, per a decade of competitor lawsuits and trade coverage: Alliant identifies a specialty team at a rival — construction, public entity, aviation, benefits — and learns, through recruiting conversations, the size of each producer’s book and current compensation. Gallagher’s 2020 Delaware Chancery complaint describes this as a “playbook”: offer outsized guaranteed compensation plus Alliant equity, sized so that the expected revenue that follows the team exceeds litigation costs and any equity infusion from Stone Point. An Alliant executive allegedly told one Gallagher target the playbook had “never failed.”

Execution is choreographed: in the June 2011 Aon raid, construction chief Peter Arkley and colleagues resigned the same morning, and within an hour their Alliant-hired lawyers filed suit in California — where non-compete enforcement is hostile to employers — seeking to void their restrictive covenants preemptively; roughly 40 Aon employees followed the same day. In April 2023, 26 members of Aon’s facultative reinsurance group resigned within hours of each other, days before May 1 renewals, and became the launch team of Alliant Re; a federal judge denied Aon’s restraining order that June. Clients, loyal to the producer rather than the letterhead, largely follow — Aon put the 2011 loss at $20M of client revenue. The retention glue is equity: producers become owners of a firm that has delivered a liquidity event roughly every four to seven years as sponsors rotated, at marks that ratcheted up from ~$1.1B in 2007 to a multiple of that today. Competitors sue; Alliant budgets for it.

Product and business overview

Alliant Specialty is the heart of the P&C franchise: named verticals in public entities (10,000+ clients — the Corbett original), construction (the Arkley franchise since 2011), real estate, energy and marine, agribusiness, healthcare, law firms, aviation, and tribal nations. Employee Benefits is a national consulting and brokerage practice serving mid-market and public-sector employers. Alliant Underwriting Solutions, branded in May 2018, is the MGA and program-administrator platform — Alliant holding the underwriting pen on carrier paper across niche programs, earning fees and commissions on both sides of the placement. Consumer/personal lines arrived with the November 2021 Confie merger, which brought the largest personal-lines distributor in the US — heavily nonstandard auto, 3,500 employees, over a million customers. Alliant Re, launched in 2023 from the lifted Aon facultative team, extends the model into reinsurance broking. The mix skews toward specialty commercial lines, the source of its above-industry growth.

Business model and pricing

Revenue books as commissions (a percentage of placed premium, typically low double digits on specialty commercial lines), fees on larger accounts, MGA program fees, and contingent/supplemental commissions from carriers. The arithmetic from company disclosures: ~$55B of premium against $5.7B+ of revenue in 2025 implies a blended take around 10 cents on the premium dollar, richer than plain-vanilla retail because of the MGA and specialty mix. The cost side is the model: guaranteed multi-year compensation packages for lifted teams front-load expense before books fully transfer, and litigation is a standing line item. Capital structure funds it — Moody’s (April 2021) noted the Confie deal was debt-funded and flagged a term loan then above $2B; the current structure includes a Term Loan B priced at SOFR+275 maturing September 2031 (SEC fund filings, 2025). S&P moved its outlook to positive in July 2025 with trailing revenue at $5.3B (March 2025) and upgraded Alliant to B+ on May 11, 2026 — still deep junk, but deleveraging.

Traction over time

Note the two organic-growth figures — BI’s 21.9% for 2024 versus S&P’s 8.6% for 2025: partly methodology (lifted teams blur the organic/inorganic line, which is rather the point), partly a softening market. Either beats the public brokers’ mid-single digits.

Market analysis

IBISWorld sizes US insurance brokers and agencies at $261.7B of revenue in 2025, with growth stalling to 0.6% that year as commercial P&C rates softened — brokers are levered to premium, and the 2019-2023 hard market that inflated commissions is unwinding. Consolidation continues regardless: MarshBerry counted 854 announced brokerage deals in 2025, the third-highest year ever, edging 2024’s 847, with platform valuations at record levels even as lower-middle-market multiples compressed toward 10-13x adjusted EBITDA (MarshBerry/PitchBook, 2025-26). The structural forces favor specialty distribution: risk complexity (climate, cyber, litigation inflation) pushes premium toward exactly the verticals Alliant runs, and the MGA channel keeps taking share of specialty placement. The structural threat is the cycle: softening rates compress the commission pool just as every consolidator’s debt got more expensive.

Competitive intel

The named set is in the sidebar; the analytical read is about methods. Marsh ($13.1B US revenue, 2026 BI ranking) and Aon ($15.4B global, 2025) own the global large-account market Alliant declines to fight for; it strip-mines their US specialty teams instead, and both have sued. Gallagher ($11.1B) is the closest strategic rival: also specialty-weighted, but it buys whole agencies at market multiples — against which the lift-out is a cost arbitrage: why pay 13x EBITDA for a firm when you can hire its revenue-producing core? Among private brokers, HUB (~$4.8B FY2024, covered here as well-positioned) is middle-market-weighted and acquisition-built; USI ($2.78B in 2024, covered here as at-risk) stagnated under the same KKR vintage Alliant outgrew; Lockton ($3.9B) is the uncomfortable comp — elite organic growth without litigation, and the firm most often bidding against Alliant for the same producers. Alliant’s edge across all of them is the equity story; its vulnerability is that the story requires ever-larger recaps to stay true.

History and evolution

1925: Robert F. Driver Co. founded in San Diego. 1977: Corbett joins as a producer; builds the public-entity practice. June 2001: Alliant Resources Group acquires Driver Co. 2007: Blackstone buys control (~$1.1B reported) from Lindsay Goldberg. June 2011: the Arkley raid — ~40 Aon construction staff in a day; a New York court (September 2012) bars solicitation of certain Aon clients; settled 2013. November 2012: KKR buys the company. June 2015: Stone Point acquires ~50%; KKR fully out by 2017. March 2017: a California jury returns a complete defense verdict for Alliant in Aon’s poaching suit; the producers are awarded $6.13M in fees. May 2018: Alliant Underwriting Solutions launches. May 2019: PSP Investments partnership. September 2020: Gallagher sues Alliant and Stone Point in Delaware Chancery over the “playbook.” November 2021: Confie merger closes. July 2022: Gallagher sues again in Illinois; settled that September. April-June 2023: 26 Aon facultative reinsurance hires launch Alliant Re; Aon’s TRO is denied. April 1, 2024: Zimmer becomes CEO. May 11, 2026: S&P upgrades to B+. June 30, 2026: Alliant ranks No. 4 among US brokers.

What people say

The case for. Producers vote with their careers: headcount grew 15% to about 14,000 in 2024 (Business Insurance, 2025), and the firm keeps landing entire senior teams from better-capitalized rivals — the strongest possible market signal about the offer. Trade press ranks Alliant the fastest-growing large US broker — 20%+ annual growth since entering the world top-10 list in 2022 (company/BI, 2026). Glassdoor sits at 3.9/5 across 536 reviews with 74% willing to recommend (2026), with praise clustering on compensation, autonomy, and the ownership culture. And in the two Aon cases that reached trial, juries sided with Alliant — the 2017 verdict rejected every claim; Insurance Journal framed the suits as “nothing personal, just routine business.”

The complaints. Competitors’ lawsuits are the loudest criticism: Gallagher’s 2020 complaint alleges systematic inducement of contract breaches and trade-secret misuse funded by Stone Point, and Insurance Business (2025) counted suits from Aon, Marsh, JLT, USI, Alera Group, and AssuredPartners within 24 months. Inside the firm, Glassdoor’s recurring negative themes are a producer-first caste system — service staff describe cliquey offices, heavy workloads, favoritism, and feeling expendable once business lands — plus, ironically for a benefits broker, expensive employee health coverage. Client-side, Confie’s nonstandard-auto book carries the chronic consumer-complaint volumes typical of that segment. The structural critiques: growth classified as “organic” is substantially purchased talent (S&P’s 8.6% for 2025 versus BI’s 21.9% for 2024 shows how elastic the definition is); guaranteed comp deals are fixed costs against books that don’t always move; the equity pitch depends on recap marks that a softening market or a rate shock could flatten; and a B+ rating still means a heavily levered balance sheet in a business with no hard assets — only people who have already proven they will leave for a better offer.

Outlook: well positioned or at risk?

Well-positioned — because Alliant’s machine converts the industry’s core weakness into its own compounding advantage, and two decades of evidence say nobody can stop it. Brokerage revenue is portable human capital; every rival’s org chart is Alliant’s acquisition pipeline, at an effective multiple far below the 10-13x+ EBITDA that MarshBerry reports for buying agencies outright. The legal system has been tested and has held for Alliant where it matters: a complete California jury verdict in 2017, a denied TRO in 2023, settlements elsewhere that never stopped the next raid. The equity flywheel is genuinely hard to copy — public brokers cannot hand out private equity with recap upside, and PE roll-ups that are not majority employee-owned cannot make the ownership pitch credible. Succession — the key-man risk of a firm built by one man since 1977 — was handled in April 2024 with an insider CEO and the lifted-out Arkley running brokerage. The risks are real: the balance sheet is junk-rated even after the May 2026 upgrade; a soft P&C market squeezes commissions while guaranteed-comp obligations stay fixed; one lost trade-secrets case with punitive damages could reprice the litigation budget; and the model’s deepest dependency — equity marks that always go up — has never been tested by a down-cycle recap. But those are risks to the pace of compounding, not to the mechanism. The mechanism is that talent flows to the best offer, and Alliant structurally makes the best offer. Until a competitor matches the equity economics or a court forbids the choreography, the No. 4 US broker keeps eating from everyone else’s table.

How a challenger would attack it

Run the lift-out on the lift-out machine. Alliant’s revenue is the same portable human capital it strips from rivals, and its producers have already proven — twice, publicly, in court — that they will leave for a better offer. A challenger with patient capital makes Alliant the target: its equity pitch depends on recap marks that have only ever gone up, and a softening P&C market compressing the commission pool while guaranteed-comp obligations stay fixed is exactly the moment the story wobbles. Offer Alliant’s stars cleaner economics — real cash partnership à la Lockton, or equity without a junk-rated balance sheet under it — and the flywheel spins in reverse. The second attack is below the producer layer: Glassdoor’s recurring theme is a producer-first caste system where service staff feel expendable, and a tech-forward specialty broker that automates servicing and pays that layer properly inherits the operational spine Alliant treats as overhead. Third, attack the accounts, not the people: Alliant’s blended ~10% take on $55B of premium is a pricing umbrella in its MGA and program business, where an AI-native MGA underwriting the same public-entity and construction niches at lower friction can win carriers’ pens on economics rather than relationships.

Same playbook, new buyer

The lift-out playbook is not insurance-specific — it works wherever revenue is producer-portable, non-competes are shaky, and equity can outbid salary: wealth management, commercial real estate brokerage, recruiting, investment banking boutiques. But the nearer opportunity stays in insurance and shifts geography and layer. Alliant’s machine is almost entirely US-domestic; the same choreography — same-morning resignations, preemptive suits in employer-hostile jurisdictions, guaranteed comp plus equity — is unrun in London specialty and European brokerage, where Marsh, Aon and WTW hold trained teams and no incumbent offers producer equity with recap liquidity. Alliant won’t follow soon: its verticals, litigation expertise, and Stone Point relationship are all tuned to US courts and US books. The second shift is downmarket: the equity-for-producers pitch aimed at the thousands of sub-$5M-revenue agency principals who are too small for Alliant’s team-level economics but face the same choice between selling to a Gallagher roll-up at a multiple or joining a platform as an owner. Alliant hires teams, not agencies — a buyer who franchises the ownership model to the long tail runs the same engine on inventory Alliant ignores.

Sources and further reading

• Alliant Insurance Services Rises to #4 on the Business Insurance Largest U.S. Brokers List — Business Wire, June 30, 2026
• Alliant Insurance Services Ranks Fifth in the U.S. and Globally on Business Insurance Largest Brokers Lists — Alliant, July 2025
• S&P revises Alliant outlook to positive as TTM revenue hits $5.3 billion — The Insurer, July 30, 2025
• Alliant Holdings L.P. Upgraded To ‘B+’ From ‘B’ — S&P Global Ratings, May 11, 2026
• Alliant, Stone Point Accused in Raid Suit of Illegal ‘Playbook’ — Bloomberg Law, September 2020
• Jury finds for Alliant in poaching fight with Aon — Business Insurance, March 2017
• Aon Sues Alliant Over ‘Unlawful Raid’ of Reinsurance Group — Insurance Journal, May 18, 2023
• Aon Denied Restraining Order Against Alliant — Insurance Journal, June 12, 2023
• The brokerage industry’s litigation epidemic: When poaching becomes a business model — Insurance Business, 2025
• KKR to Acquire Alliant Insurance Services, Inc. from Blackstone — Business Wire, November 23, 2012
• Alliant Forms Strategic Partnership with PSP Investments — PSP Investments, 2019
• Greg Zimmer Named Chief Executive Officer of Alliant Insurance Services — Alliant, January 2024
• Insurance Brokerage M&A Stays Active in 2025 Amid Market Headwinds — MarshBerry, 2026