Confirm the relevant date
Moving your tax residence between cantons and receiving a pension lump sum are subject to a specific rule. Article 4b of the tax harmonisation law assigns relevant lump sums to the canton of tax residence when the benefit falls due. For a Swiss resident, the address of the foundation holding the 3a therefore does not settle the question. Neither a payment instruction nor the date a credit appears on your bank statement necessarily establishes the due date.
When two dates differ
Suppose a benefit falls due on 10 September and you genuinely change tax residence on 20 September. If the money arrives on 25 September, the fact that the account was credited after your move does not in itself move the tax liability. If the benefit instead fell due on 25 September, the analysis could change. These dates illustrate the mechanism: the contract, reason for payout and actual circumstances determine the result.
Build a file before withdrawing
Ask the institution to confirm the due date and which tax address it is using. Gather proof of departure and arrival and record any other scheduled pension lump sums. If the two cantons might assess the facts differently or your old home remains available, ask the relevant authority how to establish your tax residence. Do not simply pick the canton whose rate table looks more favourable.
Compare scenarios you can actually use
Geneva describes a separate tax on pension benefits paid as lump sums. For two workable timelines, use the relevant cantons’ official calculators with the correct year's inputs. Include the other reportable payouts and retain the provider's certificate. Moving abroad calls for a different analysis, including withholding at source and any applicable treaty.
Distinguish the payout from the annual return
You may need to explain the withdrawal to a different authority from the one receiving your ordinary year-end return. Do not infer the competent canton from the heading on that return alone. Before moving, prepare a timeline: confirmed due date, key handover, actual move and bank credit. Seek clarification when the important dates fall close together. A change of a few days on administrative correspondence does not, by itself, establish where you actually had your tax residence.