Can I declare previously undeclared income or assets in Switzerland?

Yes, in many cases. Switzerland allows a one-time penalty-free voluntary disclosure (straflose Selbstanzeige) for previously undeclared income or assets, provided certain conditions are met. The disclosure must be complete, the tax authorities must not already be aware of the omission, and it can generally only be used once. While back taxes and interest remain payable, this process can help taxpayers regularise their tax affairs without fines.