When does withholding tax apply?
Withholding tax applies if you live abroad when withdrawing capital from second pillar pension assets (no residence or domicile in Switzerland). In this case, Switzerland has no direct access to you and therefore levies the capital withdrawal tax at source, i.e. at your pension fund.
The federal tax on the withdrawal of pension benefits at source is progressive. Different models are applied in the cantons. The pension fund must deduct the withholding tax from the pension assets and pay it to the state. You receive the net amount.
The withholding tax can be reclaimed if there is a double taxation agreement with the country in which you now live.