Surplus share reinsurance is an important tool for insurers seeking flexible, tailored solutions to manage their risk portfolios. Unlike quota share arrangements, surplus share reinsurance allows cedants to retain a portion of each policy up to a set limit, ceding only the surplus amount above that threshold.
Understanding how surplus share reinsurance works, its pros and cons, and other essential knowledge can help industry professionals make informed decisions about structuring their reinsurance programs.
In this article, we’ll explore this type of reinsurance and provide crucial information for insurers, reinsurers, and brokers worldwide.
Surplus share reinsurance is a type of proportional reinsurance arrangement where an insurer cedes only the portion of a policy’s risk that exceeds a predetermined retention limit. The insurer keeps liability up to this set amount, while any coverage above that threshold, called the surplus—is transferred to the reinsurer.
Under this reinsurance agreement, an insurer is allowed to retain a set amount of risk on each policy. This amount of risk is often referred to as the “retention” or “line”, and the insurance company cedes any coverage above that amount to a reinsurer.
When a policy’s total amount insured exceeds the insurer’s retention, the surplus portion is transferred to the reinsurer. The reinsurer then assumes a proportional share of both the premiums and any claims related to that surplus.
How would the process of applying surplus share reinsurance look like? Here are the steps:
The insurance company determines the maximum amount of risk it will retain on individual risks – this is known as the retention limit. Any coverage above this amount becomes the surplus share.
In a surplus share reinsurance agreement, the insurer cedes the surplus portion above the retention limit to the reinsurer. The reinsurer agrees to indemnify the insurer for losses on this surplus, up to a specified number of lines.
Once the insurer issues a property insurance policy that exceeds its retention, the surplus share is calculated. For example, if the retention limit is $100,000 and a policy is written for $300,000, the insurer retains $100,000 and cedes $200,000 to the reinsurer.
The insurer and reinsurer share premiums and claims on a pro rata basis, according to their respective shares of the risk.
The insurance broker and insurer ensure that all policy data, premium payments, and claims information are accurately reported and settled according to the terms of the surplus share reinsurance agreement.
This includes regular communication with the reinsurer, timely submission of bordereaux (detailed lists of policies and claims), and adherence to all treaty requirements.
When a claim arises on a policy covered by the surplus share arrangement, the insurer pays the claim to the policyholder. They then recover the reinsurer’s share of the claim, based on the proportion of risk ceded. The reinsurer reimburses the insurer for its agreed share of the loss, up to the surplus amount covered under the treaty.
At the end of the treaty period or at agreed intervals, the insurer, broker, and reinsurer review the performance of the surplus share reinsurance agreement. They evaluate loss experience, premium volumes, and any changes in the insurer’s risk profile.
Based on this assessment, they may adjust the terms, retention limit, or number of surplus lines before renewing or renegotiating the agreement for the next period.
Surplus share agreements are just among the several forms of reinsurance. Find out more about the common types of reinsurance in this guide.
Suppose an insurer specializing in home insurance enters a surplus share reinsurance agreement with a reinsurer. The insurer sets a retention limit of $500,000 per individual property risk and the treaty allows up to four surplus lines per policy. This means the insurer can cede up to $2 million in coverage above its retention for each policy.
For example, if the insurer underwrites a commercial property policy with a sum insured of $1.5 million:
Premiums and claims are shared proportionally:
If a fire causes $600,000 in damage to the insured property:
This arrangement allows the insurer to write larger policies without exceeding its risk appetite and ensures that both parties share risk and reward in direct proportion to their participation.
Surplus share reinsurance is a form of treaty agreement. Find out the differences between treaty reinsurance and facultative reinsurance in this guide.
If you’d like to know which reinsurers deal in surplus share reinsurance, here are some of the biggest names:
One of the world’s largest reinsurers, Munich Re provides a wide range of proportional reinsurance products, including surplus share reinsurance, for property, casualty, and specialty lines.
Swiss Re is a leading global reinsurer offering surplus share reinsurance as part of its treaty reinsurance solutions, serving both primary insurers and specialty markets.
Hannover Re is known for its flexible treaty reinsurance programs, including surplus share reinsurance, and works with insurers worldwide across multiple lines of business.
SCOR, a top-tier global reinsurer headquartered in France, provides surplus share reinsurance for property, casualty, and specialty risks, with a focus on tailored treaty solutions.
Everest Re offers a full suite of treaty reinsurance products, including surplus share reinsurance. It serves clients in North America, Europe, Asia, and Latin America.
Lloyd’s is a marketplace for specialist insurance and reinsurance, where many syndicates offer surplus share reinsurance treaties, especially for property and specialty risks.
Surplus share reinsurance is one of the two types of proportional treaty reinsurance agreements. The other kind of proportional treaty reinsurance is quota share reinsurance.
Surplus share reinsurance has several similarities to its quota share counterpart. Here’s how they compare:
| Feature | Surplus Share Reinsurance | Quota Share Reinsurance |
|---|---|---|
| Type | Proportional treaty | Proportional treaty |
| Risk Sharing | Only the portion above the retention limit is ceded; varies by policy | Fixed percentage of every policy is ceded |
| Premium Sharing | Only premiums for the surplus portion are ceded, pro rata | Fixed percentage of all premiums ceded |
| Loss Sharing | Only losses above retention are shared, pro rata | Fixed percentage of all losses shared |
| Retention | Fixed dollar amount per policy (the “line”) | Fixed percentage of every policy |
| Best For | Portfolios with variable policy sizes (e.g., commercial property) | Homogeneous portfolios (e.g., auto, homeowners) |
| Flexibility | High—cession varies by policy size | Low—same percentage for all policies |
| Administration | More complex—requires calculation for each policy | Simple—uniform calculation across portfolio |
| Profit Retention | Insurer keeps all profits on policies within retention | Insurer gives up share of profits on all policies |
| Application | Applies only to policies exceeding retention | Applies to all policies in the covered portfolio |
Meanwhile, here is a comparison showing key differences between surplus share and excess-of-loss reinsurance:
| Feature | Surplus Share Reinsurance | Excess of Loss Reinsurance |
|---|---|---|
| Type | Proportional treaty | Non-proportional treaty |
| Risk Sharing | Only the portion above the retention limit is ceded; varies by policy | Reinsurer pays only when losses exceed a set retention (attachment point) |
| Premium Sharing | Only premiums for the surplus portion are ceded, pro rata | Insurer pays a negotiated premium for coverage; not proportional to risk ceded |
| Loss Sharing | Only losses above retention are shared, pro rata | Reinsurer pays losses above the retention, up to a specified limit |
| Retention | Fixed dollar amount per policy (the “line”) | Fixed dollar amount per claim, event, or aggregate period |
| Best For | Portfolios with variable policy sizes (e.g., commercial property) | Protection against large, infrequent, or catastrophic losses |
| Flexibility | High—cession varies by policy size | High—coverage can be tailored to specific risk layers or events |
| Administration | More complex—requires calculation for each policy | Moderate—requires tracking losses against retention and limits |
| Profit Retention | Insurer keeps all profits on policies within retention | Insurer retains all profits unless a loss exceeds the retention |
| Application | Applies only to policies exceeding retention | Applies to individual large claims, events, or aggregate losses |
Insurance brokers can use this type of reinsurance if the risk profile, financial objectives, and other crucial factors align with their clients’ needs. While checking its benefits, it’s sound practice to also consider their drawbacks. Here's a rundown of both:
Surplus share reinsurance enables insurers to write policies with higher coverage limits than they could on their own. By ceding the portion of risk above a set retention, insurers can safely take on larger or more varied risks without overexposing their own capital.
Note that the reinsurer, in turn, can use retrocession reinsurance to limit their own exposure and enter into a retrocession agreement with another reinsurer or retrocessionaire.
Insurers can choose a retention limit that matches their risk appetite and financial strength. Since only the surplus above this limit is ceded, this allows for tailored risk management on a policy-by-policy basis.
By transferring the surplus risk to a reinsurer, insurers can free up capital that would otherwise be tied up in large exposures. This capital efficiency supports business growth and helps meet regulatory requirements.
Premiums and claims are shared between the insurer and reinsurer in direct proportion to the amount of risk each party assumes. This alignment of interests can lead to more stable financial results.
Surplus share reinsurance is suited for portfolios that include a mix of small and large policies. The arrangement automatically adjusts the ceded amount based on the size of each policy, making it more flexible than quota share treaties.
By ceding the surplus portion of larger risks, insurers are protected from excessive losses on individual policies, helping to stabilize their financial performance and reduce volatility.
Surplus share reinsurance requires the insurer to calculate the retained and ceded portions for each individual policy, based on the retention limit and the policy’s sum insured. This adds administrative work and can complicate accounting, especially for insurers with high volumes of policies or frequent changes in policy size.
Because only the portion above the retention is ceded, smaller policies may not be reinsured at all, while larger policies may result in significant cessions. This can lead to inconsistent risk transfer across the insurer’s portfolio.
Surplus share treaties are designed to address large individual risks, not aggregate or catastrophic losses across many policies. Insurers may still be exposed to significant losses if multiple large claims occur simultaneously, unless they supplement surplus share treaties with other common forms of reinsurance.
Setting appropriate retention limits and surplus lines requires careful analysis and negotiation with the reinsurer. If not structured properly, the treaty may not provide optimal protection or could result in unfavorable terms for the insurer.
Since the reinsurer only shares in the surplus portion, their interests may not always be fully aligned with the insurer’s. This can be true for smaller risks that remain fully retained by the insurer.
Does surplus share reinsurance work the same in different parts of the world? Keep this as a handy guide if you operate in different reinsurance markets and service multinational clients.
Just remember, these rules may not apply in the long term, so it’s best to monitor any regulatory changes in your market. Here’s how this type of reinsurance is handled in different markets:
Regulation: Overseen by state insurance departments and guided by the National Association of Insurance Commissioners (NAIC)
Requirements: Surplus share treaties must meet statutory accounting and risk transfer standards. Ceded reinsurance is subject to credit for reinsurance rules. Reinsurers must be licensed, accredited, or meet collateral requirements
Disclosure: Detailed reporting of ceded premiums, recoverables, and treaty terms is required in statutory filings
Regulation: Governed by Solvency II (EU/EEA) and the Prudential Regulation Authority (PRA)/Financial Conduct Authority (FCA) in the UK
Requirements: Treaties must demonstrate effective risk transfer and be reflected in solvency capital calculations. Reinsurers must be authorized or equivalent. Contracts must be clear on risk transfer, profit sharing, and ceding commissions
Disclosure: Comprehensive documentation and transparent reporting are required for regulatory compliance.
Regulation: Varies by country, but major markets like Japan, Australia, Singapore, and Hong Kong have robust regulatory frameworks
Requirements: Local regulators may require reinsurers to be licensed or registered. Treaties must comply with local solvency and reporting standards. Some countries mandate local reinsurer participation or specific contract language
Disclosure: Regular reporting of reinsurance arrangements and recoverables is required
Regulation: Increasingly aligned with international standards, but regulatory rigor varies
Requirements: Many countries require approval of reinsurance partners and contracts, with a focus on solvency, transparency, and risk transfer
Disclosure: Local regulators may require detailed reporting and, in some cases, restrict the use of offshore reinsurers
Regulation: Regulatory maturity varies widely. Some markets (e.g., South Africa, UAE) are highly regulated, while others are still developing frameworks
Requirements: Surplus share treaties must comply with local solvency and reporting rules. International reinsurers are often required or preferred for capacity and expertise
Disclosure: Varies by jurisdiction but is increasingly moving toward greater transparency and solvency oversight
They can use surplus share reinsurance to help insurers manage large or variable risks more efficiently.
By structuring surplus share treaties, brokers enable insurers to retain only the portion of risk they are comfortable with and cede the surplus above a set retention limit to a reinsurer.
This approach allows insurers to underwrite larger policies, optimize capital usage, and stabilize their financial results. Brokers play a key role in assessing the insurer’s risk profile, negotiating treaty terms, ensuring regulatory compliance, and facilitating clear communication between all parties.
Ultimately, surplus share reinsurance helps brokers deliver tailored risk transfer solutions that align with their clients’ growth and risk management strategies.
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