Calculate incurred-but-not-reported reserves for long-tail liabilities.
IBNR 常用已报案赔款乘以发展因子推算。
| Item | Formula / Rule | Source / Standard |
|---|---|---|
| Reserve definition | IBNR = ultimate loss − reported paid losses − reported case reserves | IFRS 17 Insurance Contracts, Appendix B |
| Development approach | Each accident year's paid losses are developed to ultimate by chain-ladder factors, the gap being the unreported portion | Mack 1993, ASTIN Bulletin 23(2) |
| Adequacy test | Claim reserves must pass an adequacy test, with any deficiency recognised in profit or loss | IFRS 17 Insurance Contracts, par. 55 |