Definition: The IBNR, which is the abbreviated form of incurred but not reported reserves (IBNR), are the reserves for claims that become due with the occurrence of the events covered under the insurance policy, but have not been reported yet. The IBNR reserves can be computed using methods like Incurred Chain Ladder, Paid Chain Ladder, Paid Bornhuetter-Ferguson etc.

The IBNER, which is the abbreviated form for incurred but not enough reported reserves, are the claim applications made wherein the losses have been reported but not adequately.

Description: For a given period, occurrence of any event insured under an insurance contract leads to claims becoming due for the company. They may or may not go reported in the same period. Insurance companies have provisions for these claims in the form of reserves such as the IBNR or IBNER reserves.

These reserves are also kept for situations where the existing reserves may prove insufficient for the claims that have been understated.