Gabriel Zucman

And second, even for that form of wealth, we know how to value it.

If you have a Picasso, and I'm sure that's the case for many of you, it's going to be insured.

So there's an insurance value and you can use it for the wealth tax.

It's a lot of money.

Globally, we're talking about 400 billion.

$50 billion in tax revenue, so about 0.4% of world GDP.

To give you a sense of how big this is, this is more than all the money that we spend globally on development aid and all international agencies combined.

But what I want to stress is that it's also a lot of money for the U.K.,

Because we don't need an international agreement and we should not wait for an international agreement before we start taxing billionaires.

Any country can do it on its own.

And if the UK was to do it on its own, it would bring about 15 billion dollars.

in tax revenue each year.

And let me just walk you through the arithmetic and then we can discuss whether it makes sense for one country to do it alone.

But in the UK, if you look at the Sunday Times rich list... Yeah, out recently.

Out recently, you see that the super rich in the Sunday Times rich list, they own in wealth the equivalent of 25%.

of the UK's GDP.

That's incredible.

It was 5% in 1989, the first year of the Sunday Times rich list, and it has increased from 5% to 25%.

Now you tax this 25%

at 2%, and you get, roughly speaking, 0.5% of GDP in tax revenue, which is 15 billion pounds per year.