Based on the information provided by the non-working person or the previous year's figures, the compensation office determines the provisional instalments at the beginning of the contribution year. The definite contributions are established as soon as notification is received from the cantonal tax office. The difference between the provisional instalments and the definite contributions is repaid or invoiced by the compensation office.

In case of significant changes in income or assets, it is advisable to inform the compensation office so that the instalments can be adjusted accordingly.
If the difference between the instalments and definite contributions is greater than 25%, the statutory interest on arrears of 5% p.a. will be charged.

More details:

Leaflet 2.03 - Non-employed contributions to Old-Age and Survivors' Insurance (OASI), Disability Insurance (DI) and Income Compensation Insurance (IC)