Field help: Application for review of capital gains:

If you want to check whether your personal tax rate results in a lower tax burden on your capital gains than the withholding tax, please select "Most favourable rate test for all capital gains". In the case of spouses / civil partners assessed together, the application can only be made jointly for both spouses / civil partners. All investment income of both spouses must be declared for the most favourable rate test.

If, on the other hand, you want only a partial review of withholding tax, please select "Review of withholding tax for certain capital gains". You can choose partial withholding if you do not want to include all capital gains in your tax return and circumstances indicate that the withholding amounts withheld by the bank were too high for individual capital gains.