Reinsurance is often described as “insurance for insurers,” but the way that protection is purchased matters. Swiss Re identifies treaty and facultative as the two basic forms of reinsurance. Understanding that distinction makes many other reinsurance terms easier to follow.
Treaty and facultative at a glance
| Feature | Treaty reinsurance | Facultative reinsurance |
|---|---|---|
| Scope | A portfolio or defined class of policies | A single policy, risk or specified exposure |
| Underwriting | Terms apply automatically to business that fits the treaty | Risk is individually submitted and evaluated |
| Speed / scale | Efficient for recurring volumes | More bespoke and transaction-specific |
| Typical use | Portfolio capacity, catastrophe protection, earnings stability | Large, unusual or treaty-excluded risks |
How treaty reinsurance works
An insurer and reinsurer agree in advance on a category of business, limits, exclusions, attachment points, pricing mechanics and other terms. When the primary insurer writes risks that meet the treaty conditions, those risks fall within the agreed reinsurance framework without a separate negotiation for every policy.
This makes treaty reinsurance suitable for portfolios such as property, casualty, motor or catastrophe exposure where the insurer needs repeatable capacity.
How facultative reinsurance works
Facultative reinsurance focuses on a specific risk. Munich Re describes facultative protection as reinsurance that can be tailored to individual or high-risk exposures. The primary insurer submits information about the risk, the reinsurer decides whether to participate, and the parties agree terms for that placement.
Examples can include a very large industrial facility, a high-limit liability account, a complex construction project or a risk that exceeds the capacity available under an existing treaty.
Facultative does not mean “better”
The two forms solve different problems. Treaty is efficient when the insurer wants broad, automatic portfolio support. Facultative is efficient when a specific account needs separate attention. Using facultative for every ordinary risk would create unnecessary friction; relying only on treaty could leave insufficient capacity for exceptional accounts.
Where proportional and non-proportional structures fit
Treaty vs. facultative describes how the business is arranged. Proportional vs. non-proportional describes how premiums and losses are shared.
- Proportional: insurer and reinsurer share premiums and losses in an agreed proportion, such as quota share or surplus structures.
- Non-proportional: the reinsurer responds when losses exceed an agreed retention or attachment point, such as excess-of-loss protection.
Swiss Re’s reinsurance education materials specifically distinguish the treaty/facultative dimension from proportional/non-proportional methods.
Why insurers combine both
A primary insurer might use a property catastrophe treaty to protect its portfolio from severe aggregated losses, then purchase facultative reinsurance for an individual industrial property whose value is too large for normal treaty capacity. The combined structure allows broad protection while retaining flexibility.
Questions that shape a reinsurance programme
- How much capital can the insurer retain per risk and per event?
- Which classes create peak catastrophe accumulation?
- What business falls outside the treaty’s appetite or limits?
- How much volatility can earnings tolerate?
- What credit, collateral and counterparty requirements apply?
- How do reinstatements, exclusions and aggregation clauses behave?
Why the distinction matters beyond insurers
Reinsurance capacity can influence how much primary insurance an insurer is willing to write, where it can grow, and how it manages large risks. Brokers and corporate buyers may encounter facultative placements when a single account needs additional capacity, while treaty arrangements often remain behind the scenes.
Frequently asked questions
Is facultative reinsurance only for bad risks?
No. It can be used for high-value, unusual or strategically important risks that simply do not fit normal treaty parameters.
Does treaty reinsurance cover every policy an insurer writes?
No. A treaty has defined scope, limits and exclusions. Business outside those terms may remain retained or require other reinsurance.
Can facultative reinsurance be proportional?
Yes. Treaty/facultative and proportional/non-proportional are different dimensions of structure.
Why would an insurer use both?
Treaty provides efficient portfolio capacity, while facultative gives flexibility for individual risks that need special treatment.
Sources & further reading
Reviewed against major reinsurance-industry educational resources in September 2026. Actual treaty and facultative contracts are bespoke legal agreements.
