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IBNR: Definition, Calculation, and Real-World Examples

Last updated 03/14/2024 by

Silas Bamigbola

Edited by

Fact checked by

Incurred but not reported (IBNR) is a vital concept in the insurance industry. This article explores IBNR, its significance, and how it’s calculated. Learn how IBNR helps insurers manage claims efficiently and prepare for unforeseen events.

Understanding incurred but not reported (IBNR)

Incurred but not reported (IBNR) is a crucial reserve account used in the insurance industry to prepare for claims and events that have occurred but haven’t been reported to an insurance company yet. This concept is especially significant in situations where there is a time gap between when a loss event happens and when it’s officially reported.

How IBNR works

IBNR is frequently utilized by insurance companies, particularly in regions prone to natural disasters, like the East and Gulf Coasts of the United States. When a catastrophic event, such as a hurricane, occurs, actuaries estimate the potential damage and projected claims. Based on these calculations, a reserve fund is established to cover these anticipated claims. Despite the fact that the losses have occurred, they haven’t been officially reported to the insurer.

Common scenarios requiring IBNR

Various scenarios necessitate the use of IBNR reserves. One such scenario is the delayed reporting of occupational disease claims in workers’ compensation cases. Diseases like silicosis, asbestosis, and certain cancers related to occupational exposures may have a long latency period, resulting in delayed reporting. Additionally, claims related to defective products or product liability, such as lead-based paint, asbestos insulation, and defective drywall, often face delayed reporting.
Poor environmental practices can also lead to delays in reporting environmental liability claims. Lastly, short-term workers’ compensation injuries and healthcare claims can also experience reporting delays in group healthcare plans.

Insurance coverages requiring IBNR

Delayed reporting affects several types of insurance coverages, where an IBNR calculation is essential. These include workers’ compensation, environmental and pollution coverage, healthcare insurance, general liability coverage, and product liability coverage. In these cases, IBNR helps insurance companies account for future claims that have already occurred but not yet reported.

Calculating IBNR

Determining the correct formula for calculating IBNR is a challenging task within the insurance industry. Insurance claim variables are often non-normally distributed, making accurate estimates problematic. Inaccurate estimates can lead to a skewed perception of an insurer’s financial health, potentially resulting in unfavorable actions against the company.
Actuaries play a crucial role in calculating IBNR. They typically consider various data points, including claim amounts, claim numbers, claim payment dates, claim settlement expenses, the class of business, intimation date, loss date, policy details, product type, and reinsurance information. Accurate calculations ensure that insurance companies are adequately prepared to meet their financial obligations.

The significance of IBNR

IBNR is a financial safety net for insurance companies. By setting aside reserves to cover claims that have occurred but not yet been reported, insurers can ensure they have the funds necessary to meet their obligations to policyholders. This is especially critical in situations where there may be a significant delay in reporting, such as natural disasters or latent disease claims.

Pros and cons of IBNR

Weigh the risks and benefits
Here is a list of the benefits and drawbacks to consider.
  • Financial preparedness: IBNR helps insurers prepare for future claims efficiently.
  • Stability: It ensures financial stability and prevents financial distress due to unexpected claims.
  • Compliance: Insurance companies comply with regulatory requirements by maintaining IBNR reserves.
  • Capital tie-up: Keeping funds in IBNR reserves can tie up capital that could be invested elsewhere.
  • Overestimation: Inaccurate IBNR estimates may lead to capital being unnecessarily tied up.
  • Complex calculations: Calculating IBNR accurately can be challenging.

The role of IBNR in risk management

Insurance companies rely on IBNR to manage various types of risks effectively. For instance, consider a general liability insurance policy covering product liability claims. In this scenario, if a manufacturer’s product causes harm, the actual loss may have occurred but not yet been reported to the insurer.

Example: Product liability

Imagine a company that produces a widely used consumer product. Over time, it becomes apparent that a component in the product is defective and causes injuries to users. The injuries occur gradually, and it takes months or even years for victims to discover the connection between their injuries and the product. In this case, the losses are incurred as soon as the injuries occur, but the claims are not reported until much later. IBNR reserves are crucial to ensure that funds are available when these delayed claims are finally reported.

IBNR in health insurance

IBNR is also a critical concept in health insurance. Health insurance providers face challenges related to delayed reporting due to the nature of healthcare services. Let’s explore how IBNR applies in this context.

Example: Group healthcare plans

In a group healthcare plan, employees receive medical services throughout the year. Some medical expenses, like surgeries or treatments, may not be reported until months after the services are rendered. This delay in reporting means that the insurer must set aside reserves for these claims, even if they haven’t been officially reported. This ensures that the insurer can cover these medical expenses when they are eventually reported.

IBNR in reinsurance

Reinsurance companies, which provide insurance to other insurers, also use IBNR to manage their risk. Reinsurers face unique challenges when estimating IBNR reserves due to the complexity of reinsurance agreements and the potential for long-tail claims.

Example: Catastrophic events

Consider a reinsurance company that provides coverage to primary insurers for catastrophic events like earthquakes. When a severe earthquake occurs, the primary insurers may have claims that exceed their own resources. Reinsurers may need to estimate IBNR reserves for potential claims that primary insurers will report in the future. This is particularly important for long-tail events like environmental damage that may not become evident immediately.


Incurred but not reported (IBNR) is a fundamental tool in risk management for insurance companies and reinsurers. It allows them to set aside funds for claims that have already occurred but haven’t been officially reported. Examples from various insurance segments, including product liability, health insurance, and reinsurance, illustrate the importance of IBNR in ensuring financial stability and meeting policyholder obligations.

Frequently Asked Questions about incurred but not reported (IBNR)

What is IBNR in insurance?

IBNR stands for “Incurred But Not Reported” and is a reserve account used by insurance companies to set aside funds for claims that have occurred but haven’t been officially reported.

Why is IBNR important for insurance companies?

IBNR is essential because it helps insurance companies prepare for claims that have already occurred but haven’t been reported. This is crucial for situations with delayed reporting, such as natural disasters or latent disease claims.

How do actuaries calculate IBNR?

Actuaries calculate IBNR by considering various data points, including claim amounts, claim numbers, claim payment dates, claim settlement expenses, and other factors. Accurate calculations are vital to ensure financial preparedness.

What are the pros of using IBNR?

The pros of using IBNR include financial preparedness, stability, and compliance with regulatory requirements. It ensures that insurers can meet their obligations to policyholders, even in the face of delayed claims.

What are the cons of using IBNR?

The cons of using IBNR include capital tie-up, as funds are held in reserves, and the potential for overestimation, which may lead to unnecessarily tied-up capital. Additionally, calculating IBNR accurately can be challenging.

Key takeaways

  • IBNR is an insurance reserve account for claims that have occurred but not yet been reported.
  • It’s often used in situations with delayed reporting due to various factors.
  • Actuaries estimate potential damages, and insurance companies set up reserves for expected losses in IBNR situations.

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