Tax on US stock dealing

Yes, if you’ve recently opened your T212 account the W8BEN form would be completed for you. If your account is fairly old you may have to do it manually, and I would just context them about it. And yeah since the ISA is tax free for deposits up to £20,000, you don’t have to worry about declaring it anywhere unless you deposit more that this. ISAs are very easy to keep on top of. Just to note though, you have a £20,000 total ISA allowance, not £20,000 for each ISA type. So if you have a cash ISA for example, the deposits you’ve put in this year will count towards your allowance. Hope this helps.