- What starts the clock
- Ablauf des Kalenderjahres, fuer welches die Beitraege geschuldet sind, that is the end of the calendar year for which the contributions are owed
- How long
- Within five years after the end of that calendar year (with a one year extension from finalization of the tax assessment for certain self employed and non employed contributions under Art. 6, 8 and 10)
- What is lost
- Sie koennen nicht mehr eingefordert oder entrichtet werden, that is the contributions can no longer either be demanded by the compensation fund or paid by the person or employer who owes them; the right is extinguished on both sides.
AHVG Art. 16 Abs. 1 sets a five year rolling forfeiture rule for AHV contributions owed. If contributions are not asserted by a formal Verfuegung (decision) within five years of the end of the calendar year for which they are owed, they can no longer be either collected by the compensation fund or paid by the insured or employer. The same paragraph extends this by one further year for certain self employed and non employed persons' contributions where the deadline runs instead from the calendar year in which the relevant tax assessment became final.
What the source does not say
The page we read does not say whether or how this five-year rule interacts with the separate gap-filling mechanism under Art. 29bis Abs. 4 AHVG, which closes contribution gaps through later contributions. This entry rests only on what Art. 16 Abs. 1 itself states, not on any assumption that gap filling has its own five-year rule.