Thanks for this detailed explanation. Are you referring to level 1 withholding tax according to dataset 1? It is my understanding that 0% withholding tax is not the most prototypical example since most countries have more than 0% withholding tax. Feel free to disagree with me on that.
Still, I’m interested in understanding the details of your example. Assuming I hold VT at IB. When HSBC pays their dividends (let’s say the dividend is 100), VT receives the full amount, 0% withholding. Assuming I have filled my W8-BEN, VT pays me 100-15=75. Assuming I get the full Swiss tax credit through DA-1, I get 15 back when I declare VT on my tax return. So my loss is 0.
Alternatively, assuming I hold VT at Saxo, Saxo pays me 70. I can get 15 back through DA-1 and 15 back through R-US.
Looking at the overall picture, I am wondering how much of the Swiss population would, like me, have a 0 loss in this example if they filed everything correctly. In a wild and completely uneducated guess I would assume that 70-80% of Swiss population above the age of 25 and with a C permit or Swiss citizenship would have 0 loss. For people with B permit and Quellensteuer, it is probably much less.