[pavlov]

Such a wealth tax existed in Nordic countries in the late 20th century, at least.

Wealth taxes in Sweden and Finland were eliminated around 2005 because capital gains tax was considered more equitable to various wealth classes and more easily administrated. The wealth tax laws had become a nest of loopholes that brought in relatively little income in the end.

It would be interesting to see a new wealth tax designed for the digital era.

[devilsavocado]

There are still a few countries with wealth taxes[0]. I'm not sure if they work well or not for these countries. Picketty doesn't spend to much time on the subject of existing wealth taxes. He is more focused on a global wealth tax, which is much more ambitious. Something that would need to be designed for the digital era indeed.

Amusing find from the linked article: Back in 1999 Trump proposed a one time wealth tax of 14.25% for individuals worth more than 10 million.

[0] https://en.wikipedia.org/wiki/Wealth_tax