Reinsurance Treaty Calculator

Treaty reinsurance covers an entire portfolio or class of business under a pre-negotiated agreement — the reinsurer commits to accept all qualifying business within the treaty's scope without individual risk selection. Treaty reinsurance provides the ceding company with certainty about reinsurance availability and is used for ongoing portfolio management. Facultative reinsurance is placed on a risk-by-risk basis — the ceding company shops individual risks in the reinsurance market and the reinsurer decides whether to accept each submission. Facultative reinsurance is used for large or unusual individual risks that exceed treaty limits, for classes of business excluded from existing treaties, or when a risk has unusual characteristics requiring individual pricing. Treaty reinsurance is far more common by premium volume, while facultative is essential for large individual risk placements in property, marine, aviation, and specialty lines.

A ceding commission (also called an acquisition commission or cedant's profit commission) is the percentage of the ceded premium that the reinsurer pays back to the ceding company. It is the reinsurer's contribution toward the original insurer's policy acquisition costs (agent commissions, marketing) and administrative expenses. Ceding commissions typically range from 20–35% of ceded premium for quota share treaties. A sliding scale commission adjusts the ceding commission based on the treaty's actual loss ratio — if losses are lower than expected, the cedant earns a higher commission; if losses are worse, the commission is lower, aligning incentives. From the ceding company's perspective, the ceding commission reduces the net cost of reinsurance. From the reinsurer's perspective, the commission reduces the effective premium available to pay claims and generate profit, making it a key negotiating point in treaty terms.

Insurance companies use reinsurance for multiple interconnected purposes. Capital management: reinsurance allows insurers to write more premium than their capital alone would permit — ceding premium and risk to reinsurers effectively leverages capital and supports premium growth. Catastrophe protection: XL treaties protect against extreme events that could threaten solvency — a single major earthquake or hurricane without reinsurance could exceed an insurer's equity. Earnings stabilization: proportional and aggregate treaties smooth the insurer's loss ratio year-over-year, making earnings more predictable for investors and rating agencies. Large risk capacity: individual risks too large for one company's capacity (a $500M commercial property, a supertanker) are made insurable through reinsurance. Regulatory capital relief: in some regulatory frameworks, reinsurance recoveries reduce required regulatory capital, improving solvency ratios. Expertise access: new entrants to specialty markets use reinsurance to access the reinsurer's underwriting expertise and risk management guidance.

Retrocession is reinsurance purchased by a reinsurer from another reinsurer (called a retrocessionaire). Just as primary insurers buy reinsurance to transfer risk, reinsurers also transfer a portion of their accumulated risk to reduce their own concentration and catastrophe exposure. The retrocessional market is a layer of the global risk transfer chain: primary insurer → reinsurer → retrocessionaire. In some complex risk transfer chains, risks pass through multiple layers of retrocession. The global retrocessional market is smaller and less liquid than the primary reinsurance market, and capacity can be severely constrained after major catastrophes when reinsurers and retrocessionaires reassess their aggregate exposures. The 2005 (Katrina/Rita/Wilma) and 2017 (Harvey/Irma/Maria) hurricane seasons caused significant retrocessional market disruptions, driving up rates for all subsequent years.

AM Best, S&P, Moody's, and Fitch all rate reinsurer financial strength, with AM Best being the most specific to the insurance industry. Reinsurer ratings assess: capital adequacy relative to the risks assumed (using models similar to Basel capital requirements for banks), underwriting profitability and loss ratio history, investment portfolio quality and duration management, management quality and strategic direction, enterprise risk management framework, and competitive position in the market. For ceding companies, reinsurer financial strength is critically important — if the reinsurer becomes insolvent, the ceding company remains liable for the original policyholder claims and loses expected reinsurance recoveries. Most professional buyers require reinsurers to carry at least an A- AM Best financial strength rating, with many requiring A or better. Diversification across multiple reinsurers (avoiding concentration with any single counterparty) is also a standard risk management practice.

Loss development refers to the process by which initially estimated losses change over time as more information becomes available. When a loss first occurs (particularly in liability insurance), the ultimate cost may not be known for years — medical treatment continues, litigation proceeds, and final settlements are reached. Actuaries use loss development triangles to project how losses reported at early maturities will ultimately develop to their final settled amounts. In reinsurance, loss development is particularly important because XL treaties may have losses that start below the retention but develop to exceed it as claims worsen over time (known as 'late developing' excess losses). Loss development assumptions are key inputs in IBNR reserve calculations, and the selection of appropriate development patterns is one of the most consequential actuarial judgments in the casualty insurance reserving process.

Traditional catastrophe excess-of-loss reinsurance pays based on the ceding company's actual insured losses from a qualifying event. This is the most common and straightforward structure. Parametric catastrophe reinsurance pays based on a trigger parameter (wind speed at a specific location, earthquake magnitude at specified coordinates) regardless of actual losses — faster payment with no loss adjustment, but basis risk exists between the parametric trigger and actual losses. Industry Loss Warranties (ILWs) pay when both the insured's losses exceed a threshold AND an industry-wide loss index (like PCS for U.S. property) exceeds a specified level. Catastrophe bonds (cat bonds) are capital market instruments that transfer catastrophe risk to investors — the issuer receives premium and principal if a triggering event occurs, while investors receive above-market yields in non-loss years. Each structure offers different trade-offs between basis risk, speed of payment, cost, and capacity.