Loss reserving refers to the calculation of the required reserves for a tranche of general insurance business. It includes outstanding claims reserves.

Typically, the claims reserves represent the money which should be held by the insurer so as to be able to meet all future claims arising from policies currently in force and policies written in the past.

Methods of calculating reserves in general insurance are different from those used in life insurance, pensions and health insurance since general insurance contracts are typically of a much shorter duration. Most general insurance contracts are written for a period of one year, and typically there is only one payment of premium at the start of the contract in exchange for coverage over the year. Reserves are calculated differently from contracts of a longer duration with multiple premium payments since there are no future premiums to consider in this case. The reserves are calculated by forecasting future losses from past losses.