Gross net written premium income (GNWPI) is the measure of the total dollar amount of premiums written by an insurer during a set period of time that are then available to be used to calculate the amount due to a reinsurer. It is used by reinsurers to calculate the amount of money they will require from an insurer in order to take on the insurer’s risks. The total amount on GNWPI consists of all the premiums that have been written by the issuing insurer (after adjusting for any refunds, cancellations or premiums paid for reinsurance coverage) and serves as the basis for calculating the reinsurer’s due amount.

GNWPI is different from gross net earned premium income (GNEPI), which uses earned premiums (transaction type) rather than written premiums (contract basis). Written premiums typically take longer to realize, as some of them may cancel before the policy’s end date. On the other hand, earners premiums are premiums that are actually earned upon the completion of the policy period. GNEPI would then be a better measure for reinsurers when the amount of risk taken on by the reinsurer increases over time.

In summary, GNWPI is a measure of the total dollar amount of premiums written by an insurer in a certain time period and then available to be used to calculate the amount due to a reinsurer. This is distinct from GNEPI, as written premiums tend to take longer to realize and can be cancelled before the policy’s end date leading to a better measure of reinsurer’s due amount.