CompanyGraph
Marsh & McLennan Companies, Inc.
MMC · NYSE Arca · United States
Helps large companies buy insurance across dozens of countries through one adviser no competitor can legally replicate.
Marsh & McLennan sits at the centre of a three-part chain that moves a multinational corporation's risk from assessment through to reinsurance: Mercer's actuaries model the exposures using proprietary software already embedded in clients' regulatory filings, Marsh then places the resulting insurance across 130 jurisdictions where it holds the local intermediary licences required by law, and Guy Carpenter routes the reinsurance into Lloyd's of London syndicates under a broker accreditation built from decades of trading history that no new entrant can simply purchase. Because each stage depends on the previous one — Lloyd's syndicates set quotation terms partly on the basis of the cession flow Guy Carpenter has historically delivered, and that flow only exists because Marsh's primary placements are generating premium — a competitor would need to replicate all three accreditation histories at once to offer a client the same coordinated coverage. The part of the business hardest to replace is not the licences, which can be acquired by buying local brokerages, but the senior brokers whose personal relationships with carriers and syndicate underwriters are what those licences are actually worth in practice, and those relationships accumulate only through years of supervised placements inside the firm. The whole chain snaps if Guy Carpenter's Lloyd's accreditation is revoked, because without it the reinsurance step disappears and the single-adviser relationship that justifies the entire arrangement loses its reason to exist.
How does this company make money?
Marsh and Guy Carpenter earn commissions from insurance carriers each time they place a policy — the bigger the premium volume, the larger the payment. Mercer earns fees for its actuarial work and consulting projects. Oliver Wyman earns fees on advisory engagements. Most of this income follows a rhythm set by annual insurance renewal seasons, with consulting revenue arriving in lumps tied to specific projects.
What makes this company hard to replace?
A new broker needs multi-year carrier appointment processes before it can access the same underwriting markets, so switching immediately creates a gap in coverage. Clients who use Mercer's actuarial systems for pension and benefits administration have their data and workflows built into those platforms, making a clean exit slow and disruptive. Guy Carpenter's reinsurance treaties renew on annual cycles that lock in placement authority for the year ahead, so even a client who wants to leave is practically tied in until the next renewal window.
What limits this company?
Growth is capped by the number of senior brokers who hold carrier appointment authority, active Lloyd's trading relationships, and client placement mandates all at once. Carriers will not honour an appointment handed to a junior broker, and Lloyd's syndicates will not quote to someone whose personal trading history they do not recognise. That kind of experience cannot be hired in — it can only be built up over years of supervised work inside the firm.
What does this company depend on?
The company cannot operate without its insurance intermediary licences across 130-plus jurisdictions, its Lloyd's of London broker accreditation, and its carrier appointment agreements with major insurers including AIG and Zurich. It also relies on the SWIFT financial messaging network to move premiums and settle claims, and on the actuarial software platforms Prophet and MoSes to run the Mercer consulting work.
Who depends on this company?
Fortune 500 multinationals depend on Marsh to keep their cross-border insurance programmes legally coordinated — without it, they would face uncovered gaps in different countries at the same time. Lloyd's of London syndicates depend on Guy Carpenter to channel specialty reinsurance business their way; if that flow stopped, their access to that category of risk would shrink. Pension fund trustees depend on Mercer's actuarial certifications to meet the fiduciary filing requirements their regulators impose.
How does this company scale?
Expanding into new countries works by acquiring local brokerages that already hold the needed licences and carrier relationships — that part can be bought. What cannot be bought is the senior broker expertise that clients and underwriters trust: those relationships live with individual people, and replacing or multiplying them cannot be done quickly or systematically.
What external forces can significantly affect this company?
Solvency II and Basel III rules push insurers to manage their capital more carefully, which increases demand for sophisticated reinsurance — but also raises the bar for compliance. GDPR and similar data privacy laws in different countries mean every multinational insurance programme must meet a patchwork of local standards. Climate change disclosure rules under TCFD are forcing new actuarial modelling capabilities, requiring ongoing investment in how physical risk is measured and reported.
Where is this company structurally vulnerable?
If Lloyd's of London revoked or seriously restricted Guy Carpenter's broker accreditation — because of a conduct finding, a rule change, or a structural reform of the Lloyd's market — the link between Marsh's primary placements and Lloyd's specialty syndicate capacity would snap. Without that link, the integrated chain that justifies one adviser handling all three stages falls apart, and multinational clients would have no reason to keep everything in one place.