How a Treaty Defines Its Portfolio
A treaty reinsurance agreement applies to a defined group of risks, rather than being negotiated separately for each one. That does not mean that every policy or claim in an insurer’s book automatically qualifies. The treaty wording determines which policies enter its scope, which losses qualify under those policies, and how the reinsurer’s share is calculated. A sound calculation therefore begins with the wording—not with a percentage applied to the entire portfolio.
The insurer that transfers part of its risk is the cedent; the party accepting that transfer is the reinsurer. For a treaty claim, first decide whether the policy and loss satisfy the agreement’s scope conditions. Only then calculate the cession under the stated terms. A claim can fail at either stage: the policy may be outside the covered portfolio, or the policy may qualify while the particular loss does not.
Scope conditions commonly specify the cedent, line of business, territory, policy or loss dates, covered perils, reporting requirements, and exclusions. Some agreements also limit the amount ceded per policy or across the portfolio. Read each condition as a separate test: satisfying one condition does not compensate for failing another.
| Wording condition | Question to ask |
|---|---|
| Cedent and class | Was the policy written by the named insurer, and is it in the covered line of business? |
| Territory or schedule | Is the risk located in an included territory or listed among covered risks? |
| Policy or loss dates | Does the wording refer to when the policy incepted, when the loss occurred, or both? |
| Perils and exclusions | Is the cause of loss covered, and does any exclusion apply? |
| Notice and limits | Was notice given on time, and do per-policy or portfolio caps restrict recovery? |
Screen First, Calculate Second
A practical way to organize the calculation is to assign each claim an eligibility indicator. Let \(I_j=1\) when claim \(j\) satisfies every applicable scope condition, and let \(I_j=0\) otherwise. Let \(X_j\) be the cedent’s covered claim payment after applying the primary policy’s terms. If the treaty cedes a stated fraction \(q\) of that payment, with no other limit, then the cession is \(C_j=I_jqX_j\). This is a calculation rule for that stated treaty term, not a claim that every treaty uses the same payment basis.
The indicator makes the screening rule explicit: an ineligible claim has \(I_j=0\), so it contributes nothing to the treaty recovery even if its dollar amount is large. If the treaty specifies a cap, apply that cap as written. For example, with a per-policy maximum recovery \(M\), a stated fraction \(q\), and an eligible payment \(X_j\), the recovery for that policy is \(I_j\min(qX_j,M)\). A portfolio cap is different: it restricts the combined recovery, and its allocation across claims must follow the treaty wording.
The fraction formula follows directly from the payment basis. For an eligible claim, the agreement transfers fraction \(q\) of the specified payment \(X_j\), so the reinsurer’s share is \(qX_j\). For an ineligible claim, the treaty transfers no share, so the recovery is zero. Summing those claim-level recoveries gives the portfolio recovery. This explains why eligibility must be settled before multiplying by the treaty percentage.
Worked Example: Distinguishing Policy Inception From Loss Date
A hypothetical treaty covers commercial-property policies written by Harbor Mutual that incept during calendar year 2027. It covers wind and fire losses occurring during each policy’s own term, provided notice reaches the reinsurer by March 31, 2028. Flood is excluded. The treaty cedes 40% of Harbor Mutual’s covered claim payment, with no per-policy or portfolio cap. The amounts below are the cedent’s payments after the primary policies’ terms have been applied.
Claim A is a covered wind loss of $18,500 under a qualifying policy. The policy incepted in 2027, the loss occurred during its term, and notice was timely. Claim B is a covered fire loss of $7,250 under a qualifying policy and also meets the loss-date and notice conditions. Claim C is a $9,000 flood loss under a qualifying policy. Claim D is a covered wind loss of $12,000 under a policy that incepted on December 1, 2027, and remains in force through November 30, 2028. The loss occurs on February 10, 2028, and is reported on March 10, 2028.
Method. Test each policy and loss against the treaty wording. In particular, the treaty requires policy inception during 2027; it does not require the loss itself to occur during 2027. For Claim D, the February 2028 loss is within the stated policy term, and the March 10 notice meets the reporting deadline.
Claims A and B qualify, so their cessions are \(0.40\times \$18{,}500=\$7{,}400\) and \(0.40\times \$7{,}250=\$2{,}900\). Claim C fails the covered-peril test because flood is excluded, so its cession is $0. Claim D qualifies: its policy incepted during 2027, its loss occurred during the policy term, and notice was timely. Its cession is \(0.40\times \$12{,}000=\$4{,}800\).
The eligible claim base is \(\$18{,}500+\$7{,}250+\$12{,}000=\$37{,}750\). The total cession is \(\$7{,}400+\$2{,}900+\$4{,}800=\$15{,}100\). The cedent retains \(\$37{,}750-\$15{,}100=\$22{,}650\) of eligible claims. As a check, \(0.40\times \$37{,}750=\$15{,}100\), matching the sum of the claim-level cessions.
Common mistake avoided: Excluding Claim D because its loss occurs after 2027 confuses a policy-inception condition with a loss-date condition. The treaty requires 2027 inception, but allows a loss during the policy’s stated term and sets a separate notice deadline.
Applying Scope Conditions and Per-Policy Limits
The treaty’s stated portfolio may be narrower than a whole line of business. For example, it may cover only listed locations or only policies issued by a particular cedent. Confirming that a loss has a covered cause is not enough if the policy itself is outside the defined portfolio. Also distinguish an amount paid by the cedent from a total loss estimate: use the treaty’s specified payment basis, not a different number simply because it appears in a claim record.
Worked Example: Checking a Scheduled Portfolio and a Per-Policy Cap
In a hypothetical agreement, a reinsurer accepts 25% of eligible paid claims on commercial equipment policies issued by Summit Indemnity for two scheduled manufacturing sites. Machinery breakdown and fire are covered; flood is excluded. Recovery is capped at $6,000 per policy. The claims have been adjusted under the primary policies, and the amounts listed are Summit’s paid claims.
Policy 1 is issued by Summit for a scheduled site and has a covered fire payment of $32,000. Policy 2 is also issued by Summit for a scheduled site and has a covered machinery-breakdown payment of $18,000. Policy 3 is for an unscheduled site and has a covered-peril payment of $12,000. Policy 4 covers a scheduled site but was issued by a different insurer; its covered-peril payment is $8,000.
Method. First check the cedent, class, scheduled location, and peril conditions. Only Policies 1 and 2 meet them. Then calculate 25% of each eligible payment and apply the $6,000 maximum separately to each policy.
For Policy 1, \(0.25\times \$32{,}000=\$8{,}000\), which exceeds the $6,000 cap. Its cession is therefore $6,000. For Policy 2, \(0.25\times \$18{,}000=\$4{,}500\), which is below the cap, so its cession is $4,500. Policies 3 and 4 each have a cession of $0: Policy 3 is outside the scheduled portfolio, and Policy 4 was not issued by the named cedent.
The eligible payment base is \(\$32{,}000+\$18{,}000=\$50{,}000\), and the total cession is \(\$6{,}000+\$4{,}500=\$10{,}500\). The cedent retains \(\$50{,}000-\$10{,}500=\$39{,}500\) of eligible claims. The $12,000 and $8,000 outside-scope claims have no treaty recovery; they are not part of the eligible base used in this reconciliation.
Common mistake avoided: Applying the percentage to every claim before checking the portfolio conditions would produce recoveries for Policies 3 and 4, even though neither is within the treaty’s scope. The per-policy cap also applies to Policy 1’s recovery, not to its underlying claim payment.
Portfolio Caps and Reconciliation
A portfolio cap limits the treaty’s total recovery across eligible claims. It is not the same as a per-policy cap: a claim may satisfy all scope conditions and have a positive uncapped recovery, yet receive a smaller recovery because earlier eligible claims have used part of the portfolio maximum. The wording must specify how a shared cap is allocated, such as by order of settlement. Do not invent an allocation rule if the agreement does not provide one.
Worked Example: Applying an Aggregate Treaty Maximum
A hypothetical treaty covers covered losses occurring in calendar year 2026 under policies issued by Vale Assurance for its listed regional equipment portfolio. It cedes 50% of each eligible paid claim, subject to a total portfolio recovery maximum of $20,000. The wording says to allocate that maximum in order of claim settlement. There is no separate per-policy cap.
Three eligible claims are settled in this order: Claim A for $24,000, Claim B for $16,000, and Claim C for $10,000. A fourth claim is for $12,000 but is a flood loss, which the treaty excludes.
Method. Screen the claims first. Claims A, B, and C meet the portfolio and loss conditions; the flood claim does not. Calculate the uncapped cession for each eligible claim, then apply the $20,000 maximum in the stated settlement order.
Before the portfolio maximum, Claim A’s cession is \(0.50\times \$24{,}000=\$12{,}000\). That leaves \(\$20{,}000-\$12{,}000=\$8{,}000\) of treaty capacity. Claim B’s uncapped cession is \(0.50\times \$16{,}000=\$8{,}000\), so it uses exactly the remaining capacity. Claim C’s uncapped cession is \(0.50\times \$10{,}000=\$5{,}000\), but no capacity remains, so its actual cession is $0. The excluded flood claim also receives $0.
The eligible claim base is \(\$24{,}000+\$16{,}000+\$10{,}000=\$50{,}000\). The total cession is \(\$12{,}000+\$8{,}000+\$0=\$20{,}000\), equal to the portfolio maximum. The cedent retains \(\$50{,}000-\$20{,}000=\$30{,}000\) of eligible claims. The actual cessions also reconcile claim by claim: $12,000 + $8,000 + $0 = $20,000.
Common mistake avoided: The uncapped 50% share of the eligible base is $25,000, but the treaty maximum reduces actual recovery to $20,000. Applying the cap without following the stated settlement order could assign that $20,000 to the wrong claims.
Common Scope and Calculation Traps
- Confusing policy dates with loss dates. “Policies incepting during 2027” does not, by itself, mean “losses occurring during 2027.” Apply each date condition to the event it names.
- Using the wrong reporting test. A loss can occur during the policy term but fail a separate treaty notice deadline. Check both conditions independently.
- Starting with the whole portfolio total. Remove out-of-scope policies and losses before calculating recoveries or reporting the eligible claim base.
- Applying a cap at the wrong level. A per-policy maximum is checked separately for each policy; a portfolio maximum applies to combined recoveries according to the treaty’s allocation wording.
- Multiplying the wrong amount. Use the payment basis stated in the treaty. If it specifies the cedent’s covered payment, do not apply the treaty percentage to an unadjusted gross loss estimate.
These distinctions matter because the portfolio recovery is a sum of claim-level decisions, not simply a percentage of all reported losses. A useful final check is to report both the eligible base and the cession, then reconcile the cedent’s retained eligible claims as eligible base minus actual cession. Keep out-of-scope amounts separate so they are not mistaken for eligible claims retained after reinsurance.
Check Your Understanding
For each problem, apply the stated scope conditions before calculating the cession. Amounts are hypothetical cedent payments after primary policy terms.
- A treaty cedes 30% of covered payments on policies issued by Alder Mutual that incept during 2026. A qualifying policy incepts on September 1, 2026, and remains in force through August 31, 2027. A covered wind loss of $10,000 occurs on January 15, 2027, and is reported by the treaty deadline. What is the cession? (Answer: $3,000)
- A treaty covers fire losses on policies issued by Birch Assurance for two scheduled warehouses, with notice due by June 30. A scheduled warehouse has a $14,000 fire claim reported June 20; another scheduled warehouse has a $9,000 fire claim reported July 2; an unscheduled warehouse has a $7,000 timely reported fire claim. If the treaty cedes 40% of eligible payments with no cap, what is the total cession? (Answer: $5,600)
- A treaty covers eligible equipment policies and cedes 20% of each paid claim, subject to a $5,000 per-policy cap. Three eligible claims are $30,000, $20,000, and $8,000. What are the three cessions and their total? (Answer: $5,000, $4,000, and $1,600; total $10,600)
- A treaty cedes 50% of each eligible claim, subject to a $15,000 portfolio maximum allocated in settlement order. Two eligible claims of $18,000 and $16,000 settle first and second; a third eligible claim is $10,000. What is the total cession? (Answer: $15,000)
- A treaty covers policies issued by Cedar Mutual that incept during 2028, covers wind but not flood, requires each loss to occur during its policy term, and requires notice by February 28, 2029. It cedes 25% of eligible payments with no cap. Claim A is a $20,000 wind loss on a qualifying policy, occurs during its term on December 20, 2028, and is reported February 15, 2029. Claim B is a $12,000 wind loss on a qualifying policy that incepted in 2027, reported on time. Claim C is a $16,000 flood loss on a qualifying policy, reported on time. What are the eligible base and total cession? (Answer: Eligible base $20,000; total cession $5,000)
This scope-first method is aligned with the SOA Exam FAM (Fundamentals of Actuarial Mathematics) syllabus.