Does a sponsorship undertaking end automatically once the sponsored person becomes a permanent resident?

No — becoming a permanent resident is what starts the sponsorship undertaking's clock, not what ends it. When a sponsor signs an undertaking, they are making a legal commitment to the government that they will support the sponsored person financially so that person does not need to turn to social assistance. Under the Immigration and Refugee Protection Regulations, that undertaking continues to run for its full length after landing — generally three years for a spousal, common-law partner, or conjugal partner sponsorship, and twenty years for a parent or grandparent sponsorship. Getting a PR card does not cut that period short.

This catches a lot of sponsors off guard. Even if the couple later separates or divorces, or a sponsored parent becomes financially independent soon after arriving, the undertaking generally keeps applying for the rest of its term unless something specific changes the sponsor's legal responsibility. If the sponsored person accesses provincial social assistance during that window, the sponsor can be asked to repay it, regardless of the state of the relationship at that point. Because these obligations run for years and can carry real financial consequences long after landing, anyone who has signed, or is considering signing, an undertaking should talk to an immigration lawyer about exactly what continues to apply in their situation.