To optimize for taxes, 3a needs to be filled with the following prioritized segments (with examples):
- WHT without credit:
- Europe ex CH
- Pacific ex JP
- EM
- No WHT
- US pension fund
- JP pension fund
- CH stocks & domicile
- WHT with credit
- CA stocks & domicile
- (US stocks & domicile)
- (CH stocks & domicile)
- (JP stocks & domicile, but only 10% credit for 15% default WHT)
This rule is disregarding actual rates of capital gains and dividends.
Edit: Some clarification