In a recent post, I asserted that

activities like tax avoidance/evasion and regulatory arbitrage aren’t peripheral flaws in a financial system primarily concerned with the efficient global allocation of capital. They are the core business, without which the profits of the global financial sector would be a tiny fraction of the $1 trillion or so now reaped annually

As I’m working on income distribution issues my long-running book project, this seems like a good time to see if this claim can be backed up by hard numbers.

First up, here’s my source for the $1 trillion number (actually $920 billion). As a plausibility check, I’ve tried to estimate the total size of the global financial sector. Various sources, including Wikipedia estimate that the banking and insurance sector accounts for 7-8 per cent of US gross product. Extrapolating to world gross product of about $80 trillion that would give around $6 trillion for the total size of the sector. The US is almost certainly more financialised than the world as a whole. Still, the profit number looks about right. A trickier question is whether the rents accruing to managers and top professional in the sector should be counted as part of profits. I’d guess that these rents account for at least another $1 trillion, but I have no real idea how to test this – suggestions welcome.

Is tax avoidance/evasion and regulatory arbitrage a big enough activity to account for a substantial share of a trillion dollars a year? Gabriel Zucman estimates that there’s $7.5 trillion stashed in tax havens, of which around $6 trillion is untaxed. He estimates the tax avoided at $200 billion . I’ll estimate that half of that ($100 billion) is creamed off in financial sector, mostly as profits or rents. That implies a profit margin of a bit under 2 per cent, which seems reasonable.

Tax evasion by wealthy individuals is only a small part of the story. Legal tax avoidance is almost certainly more important. Most of that involves companies, but it’s important to distinguish between “close” corporations, which hide the activities of an individual or family and large global corporations. I don’t have any idea how to measure the cost of avoidance through close corporations. As regards global corporations, Zucman estimates that “a third of U.S. corporate profits, or $650 billion, are purportedly earned outside the country, with a cost to the US of $130 billion a year . Extrapolating to the world as a whole, that would be at least $500 billion. Again, assuming the financial sector creams off half of the sum, we get $250 billion (the fact that the finance sector itself accounts for around 40 per cent of all corporate profits means there’s a problem of recursion that I haven’t worked through)

Then there’s manipulation of exchange rate and bond markets. I have no idea how to measure this, but given that the notional volume of trade in some of the markets concerned is measured in the hundreds of trillions, it seems plausible that the profits and rents from market-rigging must be at least in the tens of billions.

These are probably the biggest scams, but there’s also regulatory arbitrage, privatization (a huge source of rent over recent decades), domestic tax avoidance and more.

Adding them up, I’d suggest that $500 billion a year is a low-end estimate for the profits and rents associated with various forms of anti-social financial sector activity.

There’s lots of potential error around these numbers, but the order of magnitude seems reasonable to me. As against the claim that the explosion in financial sector activity and profits over the past 40 years has been driven by the benefits of a more efficient allocation of capital by rational markets, the claim that it’s all about tax-dodging and socially unproductive arbitrage seems pretty plausible.

Obviously, the social cost of a financial system devoted to undermining tax and regulatory systems far exceeds the profits earned from the activity. That’s true of any kind of socially destructive, but privately profitable, activity. But the problem is greater in the case of financial sector activity because of the disastrous effects of financial crises.