Optimal tax rate for top one per cent may be as high as 83%

Paper suggests cutting taxes may divert attention to wasteful bargaining

Via Daniel Elton, a new(ish) paper (pdf) by economists Thomas Piketty, Emmanuel Saez and Stefanie Stantcheva makes the case for the optimal tax rate of the richest one per cent could be as high as 83 per cent.

The authors look at three possible ways in which top incomes respond to marginal tax rates.

The first is the "supply side" channel cited by Arthur Laffer when he developed his concept of the Laffer curve. Under this channel, marginal tax rates that are too high result in people doing less work than they otherwise would. Lower tax rates thus respond to more economic activity, and greater growth and higher tax revenue. Laffer's work was used by the Reagan administration to justify cutting the top rate in the US, from 70 per cent down to 28 per cent.

The second is the "tax avoidance" channel. This is the model cited by the Chancellor when he made the decision to cut the tax rate for top earners in Britain from 50 per cent to 45 per cent. The argument is that high tax rates increase tax avoidance, but the authors argue – in common with many of the Chancellors critics – that tax avoidance can be dealt with directly, writing that:

A better policy would be to first close loopholes so as to eliminate most tax avoidance opportunities and only then increase top tax rates.

The third is the "compensation bargaining" channel. The authors argue that:

While standard economic models assume that pay reflects productivity, there are strong reasons to be sceptical, especially at the top of the income distribution where the actual economic contribution of managers working in complex organisations is particularly difficult to measure.

As a result, top workers have ample opportunity to set their own pay, through bargaining harder or influencing compensation committees. The incentives for this economically wasteful activity are higher the lower tax rates are. Just as with the supply side model, tax cuts increase the wealth of the richest in society, but unlike that model they do not also increase growth; rather, the extra money for the rich comes from those poorer than them.

The authors, using their estimates of the elasticity of the various channels (that is, the magnitude of the effect), then calculate what the optimum rates would be. Under the first model, they find it to be roughly 57 per cent – 5 per cent higher than the top British tax rate is until the cut takes effect (National Insurance for top earners is 2per cent). Assessing the second model (Osborne's preferred argument), they find that the optimal tax rate would be 62 per cent, but argue that if the correct anti-avoidance and simplification measures were put in place, it would be 71 per cent.

The third model, however, outputs an optimal rate of 83 per cent. The authors still assume a minor supply-side effect, making up 40 per cent of the total elasticity, which is why it isn't higher. That is, they still assume that high tax rates will encourage the rich to work less, but they also assume that they will encourage the rich to put more of their effort into actual work, and less of it into "compensation bargaining".

How to decide between models one and three (the authors assume that once anti-avoidance measures are put in place, model two is the same as model one)? The former predicts that lower tax leads to more work, the latter that it merely leads to higher pay. As a result, tax cuts should be correlated with higher growth. Are they? Well, no:

As a result, the bargaining model can at least be said to be as realistic as the supply-side model; and if that's the case, the optimal top tax rate for most nations is likely to be far in excess of where it is set now.

For more, see the authors in the Boston Review, VoxEU, or their original paper (pdf).

Pictured: Laffer. No, wait, laughers. Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Photo: Getty Images
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Autumn Statement 2015: George Osborne abandons his target

How will George Osborne close the deficit after his U-Turns? Answer: he won't, of course. 

“Good governments U-Turn, and U-Turn frequently.” That’s Andrew Adonis’ maxim, and George Osborne borrowed heavily from him today, delivering two big U-Turns, on tax credits and on police funding. There will be no cuts to tax credits or to the police.

The Office for Budget Responsibility estimates that, in total, the government gave away £6.2 billion next year, more than half of which is the reverse to tax credits.

Osborne claims that he will still deliver his planned £12bn reduction in welfare. But, as I’ve written before, without cutting tax credits, it’s difficult to see how you can get £12bn out of the welfare bill. Here’s the OBR’s chart of welfare spending:

The government has already promised to protect child benefit and pension spending – in fact, it actually increased pensioner spending today. So all that’s left is tax credits. If the government is not going to cut them, where’s the £12bn come from?

A bit of clever accounting today got Osborne out of his hole. The Universal Credit, once it comes in in full, will replace tax credits anyway, allowing him to describe his U-Turn as a delay, not a full retreat. But the reality – as the Treasury has admitted privately for some time – is that the Universal Credit will never be wholly implemented. The pilot schemes – one of which, in Hammersmith, I have visited myself – are little more than Potemkin set-ups. Iain Duncan Smith’s Universal Credit will never be rolled out in full. The savings from switching from tax credits to Universal Credit will never materialise.

The £12bn is smaller, too, than it was this time last week. Instead of cutting £12bn from the welfare budget by 2017-8, the government will instead cut £12bn by the end of the parliament – a much smaller task.

That’s not to say that the cuts to departmental spending and welfare will be painless – far from it. Employment Support Allowance – what used to be called incapacity benefit and severe disablement benefit – will be cut down to the level of Jobseekers’ Allowance, while the government will erect further hurdles to claimants. Cuts to departmental spending will mean a further reduction in the numbers of public sector workers.  But it will be some way short of the reductions in welfare spending required to hit Osborne’s deficit reduction timetable.

So, where’s the money coming from? The answer is nowhere. What we'll instead get is five more years of the same: increasing household debt, austerity largely concentrated on the poorest, and yet more borrowing. As the last five years proved, the Conservatives don’t need to close the deficit to be re-elected. In fact, it may be that having the need to “finish the job” as a stick to beat Labour with actually helped the Tories in May. They have neither an economic imperative nor a political one to close the deficit. 

Stephen Bush is editor of the Staggers, the New Statesman’s political blog.