Apparently not. Googling, no one seems to actually do it in spite of some politicians talking about it.

It seems quite a bad idea from a practical point of view.

Not so much because it's socialist but it leads to all sorts of extra paperwork for no good reason. Like say you buy some utility company share for your retirement in 20 years and it fluctuates. Do you want to be valuing it and paying tax and then claiming it back when it goes down every year for 20 years or just declare the gain at the end?