In January this year, Senator Elizabeth Warren unveiled a proposal to tax the wealth of the richest 0.1% of Americans. The proposed legislation to tax households with a net worth of $50 million or more draws on analysis by one of our US panel of economic experts – Emmanuel Saez at Berkeley – showing that the richest 0.1% has seen its share of American wealth more than triple from 7% to 22% since the late 1970s. Saez and colleagues have also made calculations of the potential impact of Senator Warren’s proposed tax.

We invited our US panel to express their views on three separate issues related to the wealth tax: first, how difficult it would be to enforce; second, assuming it could be enforced successfully, what would be its likely effects; and third, whether there were realistic alternatives within the existing US tax system. We asked the experts whether they agreed or disagreed with the following statements, and if so how strongly and with what degree of confidence:

(a) Senator Warren’s proposed wealth tax would be much more difficult to enforce than existing federal taxes because of difficulties of valuation and the ways by which the wealthy can under-report their true wealth.

(b) If successfully enforced, Senator Warren’s proposed wealth tax would substantially decrease the share of wealth going to the top 0.1% of wealth-holders after 20 years.

(c) A public policy goal that could be accomplished with a well-enforced wealth tax could be equally accomplished with modifications to existing federal taxes – for example, revising the estate tax and/or capital gains tax.

Enforcement

Of our 42 experts, 39 participated in this survey. On the first statement, only one expressed no opinion; and weighted by each expert’s confidence in their response, 34% strongly agreed, 48% agreed, 9% were uncertain, and 9% disagreed. In other words, a substantial majority of respondents considered the wealth tax to be much more difficult to enforce than existing federal taxes.

Among the short comments that the experts are able to include when they participate in the survey, some pointed to past experiences of the challenges of enforcing a wealth tax. Steven Kaplan at Chicago stated that: ‘Where they have been tried, wealth taxes have not been successful’; and Darrell Duffie at Stanford added: The experience in France is apparently that this is a difficult form of tax to implement’.

Others who agreed with the statement commented on the difficulties of enforcement of wealth taxes compared with other taxes: Christopher Udry at Northwestern said they were: ‘Much more difficult than income taxes. The transition to appropriate reporting and record keeping for a wealth tax difficult but feasible.’ Larry Samuelson at Yale commented: ‘Wealth is notoriously difficult to tax. Enforcement problems are compounded by the distortions induced by legal tax evasion.’ And Anil Kashyap at Chicago pointed to the challenge of valuation: ‘Paintings, private businesses, long held property without obvious comparables in multiple locations – all hard to value’.

Others were a little less skeptical, including two who answered that they were uncertain: Abhijit Banerjee at MIT asked: ‘It will be more difficult to implement, but much more? There will be a one-time investment in learning, closing loopholes’; and Jonathan Levin at Stanford noted: ‘It would be difficult, but other parts of the tax code are also very complex to enforce’. Judith Chevalier at Yale, who agreed with the statement, added: ‘There are challenges. Not clear that they would be greater than for the estate tax.’

Aaron Edlin and Emmanuel Saez at Berkeley, both of whom disagreed with the statement, mentioned ways to make the wealth tax enforceable. Edlin commented on valuation issues: ‘One way to avoid under reporting with some assets is to allow anyone to buy at declared valuations. Another is large penalties’; and Saez referred to the resource requirements of tax collection: ‘enforcement success depends on resources devoted to set up a systematic way to measure wealth: information sharing, norms for valuations etc’.

Impact

On the second statement, three respondents expressed no opinion; and weighted by each expert’s confidence in their response, 19% strongly agreed, 54% agreed, 15% were uncertain, 6% disagreed, and 6% strongly disagreed – so just under three quarters agreeing that a successfully enforced wealth tax would substantially decrease the share of wealth going to the top 0.1% of wealth-holders.

In comments, Darrell Duffie said: ‘Conditional on successful enforcement, a simple calculation shows a substantial impact, assuming the revenues are redistributed naturally’;
Larry Samuelson calculated that ‘If successful, taxation at rates of two or three percent, compounded over twenty years, would significantly diminish the taxed wealth’; and Emmanuel Saez noted that ‘Wealth tax mechanically reduces returns to wealth at the top. Behavioral responses likely to magnify the effect. Effect builds up over time’.

Robert Shimer at Chicago, who agreed with the statement, added that: ‘It would also lead to much of the wealth moving offshore, despite provisions against that’; while Steven Kaplan, who strongly disagreed, argued that: ‘Pre-tax wealth inequality is driven by technology and globalization. Wealth taxes do not change those two forces’.

Respondents who were uncertain about the impact returned to the condition of successful enforcement. Richard Thaler at Chicago commented: ‘I don’t know how we get to “successfully enforced”. We can’t collect the estate tax, why would we be able to enforce this?’

Alternatives

On the third statement, two respondents expressed no opinion; and weighted by each expert’s confidence in their response, 13% strongly agreed, 47% agreed, 13% were uncertain, and 27% disagreed – so just under two thirds suggesting that alternative means could achieve the objectives of a wealth tax.

Among those who agreed or strongly agreed with the statement, Michael Greenstone at Chicago said that: ‘a reform of existing taxes to match wealth tax however would need to do something about the stepping up of cost basis for estate taxes’. Richard Thaler concurred: ‘Yes, the estate tax is a sieve. Start with that? Get rid of step up to begin with’; as did Judith Chevalier: ‘To use only income and capital gains taxes, a key policy lever would be eliminating the capital gains basis step up at death’.

Among others who agreed with the statement, Daron Acemoglu at MIT suggested the following: ‘What would be most successful would be a combination of relatively high estate taxes combined with taxes on capital income’. In his comment on the first statement on enforceability, he noted that: ‘Taxing capital income at the same rate as labor income would be simpler, more effective and much less difficult to implement.’

Robert Hall at Stanford said: ‘We should focus on a progressive consumption tax structured as a value-added tax’; while William Nordhaus at Yale proposed: ‘Start with enforcing the current laws. This would be highly progressive move and should be at top of tax agenda, way at top’.

Among those who disagreed with alternative approaches, Emmanuel Saez commented that: ‘Estate and realized capital gains taxes come decades after wealth accumulation => wealth tax is a useful withholding tax back stop’; while Christopher Udry concluded that: ‘Unless the changes in capital gains and inheritance taxes were radical, they can’t match the time path of the wealth tax’.

Evidence

Pete Klenow at Stanford provided links to related research evidence: first, on the impact of US enforcement efforts to tax offshore accounts; second, a model of optimal progressive capital income taxes by Emmanuel Saez; and third, a comparison of the efficiency and distributional effects of wealth taxation and capital income taxation.

All comments made by the experts are in the full survey results.

Romesh Vaitilingam
@econromesh
April 2019

Question A:

Senator Warren’s proposed wealth tax would be much more difficult to enforce than existing federal taxes because of difficulties of valuation and the ways by which the wealthy can under-report their true wealth.

Responses weighted by each expert's confidence

Question B:

If successfully enforced, Senator Warren’s proposed wealth tax would substantially decrease the share of wealth going to the top 0.1% of wealth-holders after 20 years.

Responses weighted by each expert's confidence

Question C:

A public policy goal that could be accomplished with a well-enforced wealth tax could be equally accomplished with modifications to existing federal taxes – for example, revising the estate tax and/or capital gains tax.

Responses weighted by each expert's confidence

Question A Participant Responses

Participant University Vote Confidence Bio/Vote History
Acemoglu
Daron Acemoglu
MIT
Agree
4
Bio/Vote History
Taxing capital income at the same rate as labor income would be simpler, more effective and much less difficult to implement.
Alesina
Alberto Alesina
Harvard
Uncertain
7
Bio/Vote History
Altonji
Joseph Altonji
Yale
No Opinion
Bio/Vote History
Auerbach
Alan Auerbach
Berkeley
Agree
7
Bio/Vote History
Autor
David Autor
MIT
Agree
5
Bio/Vote History
Baicker
Katherine Baicker
University of Chicago
Agree
3
Bio/Vote History
Banerjee
Abhijit Banerjee
MIT
Uncertain
6
Bio/Vote History
It will be more difficult to implement, but much more? There will be a one-time investment in learning, closing loopholes.
Bertrand
Marianne Bertrand
Chicago
Disagree
4
Bio/Vote History
Brunnermeier
Markus Brunnermeier
Princeton
Uncertain
3
Bio/Vote History
Chetty
Raj Chetty
Harvard Did Not Answer Bio/Vote History
Chevalier
Judith Chevalier
Yale
Agree
5
Bio/Vote History
There are challenges. Not clear that they would be greater than for the estate tax.
Cutler
David Cutler
Harvard
Agree
1
Bio/Vote History
Deaton
Angus Deaton
Princeton
Agree
7
Bio/Vote History
Duffie
Darrell Duffie
Stanford
Agree
1
Bio/Vote History
The experience in France is apparently that this is a difficult form of tax to implement.
Edlin
Aaron Edlin
Berkeley
Disagree
5
Bio/Vote History
One way to avoid under reporting with some assets is to allow anyone to buy at declared valuations. Another is large penalties.
Eichengreen
Barry Eichengreen
Berkeley
Agree
5
Bio/Vote History
Einav
Liran Einav
Stanford
Agree
1
Bio/Vote History
Fair
Ray Fair
Yale
Strongly Agree
5
Bio/Vote History
Finkelstein
Amy Finkelstein
MIT Did Not Answer Bio/Vote History
Goolsbee
Austan Goolsbee
Chicago
Strongly Agree
10
Bio/Vote History
Greenstone
Michael Greenstone
University of Chicago
Strongly Agree
5
Bio/Vote History
Hall
Robert Hall
Stanford
Agree
5
Bio/Vote History
Holmström
Bengt Holmström
MIT
Strongly Agree
5
Bio/Vote History
Hoxby
Caroline Hoxby
Stanford
Strongly Agree
10
Bio/Vote History
Hoynes
Hilary Hoynes
Berkeley
Agree
7
Bio/Vote History
Judd
Kenneth Judd
Stanford
Agree
8
Bio/Vote History
Kaplan
Steven Kaplan
Chicago Booth
Strongly Agree
10
Bio/Vote History
Where they have been tried, wealth taxes have not been successful.
Kashyap
Anil Kashyap
Chicago Booth
Strongly Agree
9
Bio/Vote History
Paintings, private businesses, long held property without obvious comparables in multiple locations -- all hard to value.
Klenow
Pete Klenow
Stanford
Agree
3
Bio/Vote History
Levin
Jonathan Levin
Stanford
Uncertain
3
Bio/Vote History
It would be difficult, but other parts of the tax code are also very complex to enforce.
Maskin
Eric Maskin
Harvard Did Not Answer Bio/Vote History
Nordhaus
William Nordhaus
Yale
Strongly Agree
8
Bio/Vote History
Saez
Emmanuel Saez
Berkeley
Disagree
10
Bio/Vote History
Enforcement success depends on resources devoted to set up a systematic way to measure wealth: information sharing, norms for valuations etc
Samuelson
Larry Samuelson
Yale
Agree
8
Bio/Vote History
Wealth is notoriously difficult to tax. Enforcement problems are compounded by the distortions induced by legal tax evasion.
Scheinkman
José Scheinkman
Columbia University
Agree
6
Bio/Vote History
Although estimates of compliance vary across countries.
Schmalensee
Richard Schmalensee
MIT
Strongly Agree
7
Bio/Vote History
Shapiro
Carl Shapiro
Berkeley
Agree
7
Bio/Vote History
Question is unclear -- which existing federal taxes? Estate tax seems most relevant.
Shimer
Robert Shimer
University of Chicago
Agree
5
Bio/Vote History
Similar difficulty to the estate tax, except it has to be assessed on everyone.
Stock
James Stock
Harvard
Agree
3
Bio/Vote History
Thaler
Richard Thaler
Chicago Booth
Agree
1
Bio/Vote History
Don't like the Q. Define "much". And the main reason I think this is harder is that it would be annual. Also unclear who has to file.
Udry
Christopher Udry
Northwestern
Agree
6
Bio/Vote History
Much more difficult than income taxes. The transition to appropriate reporting and record keeping for a wealth tax difficult but feasible.

Question B Participant Responses

Participant University Vote Confidence Bio/Vote History
Acemoglu
Daron Acemoglu
MIT
Uncertain
2
Bio/Vote History
"successful enforcement" is very difficult to define and achieve. Hence uncertain.
Alesina
Alberto Alesina
Harvard
Disagree
6
Bio/Vote History
Altonji
Joseph Altonji
Yale
No Opinion
Bio/Vote History
Auerbach
Alan Auerbach
Berkeley
Agree
5
Bio/Vote History
Autor
David Autor
MIT
Disagree
5
Bio/Vote History
Baicker
Katherine Baicker
University of Chicago
Uncertain
3
Bio/Vote History
Banerjee
Abhijit Banerjee
MIT
Agree
7
Bio/Vote History
Bertrand
Marianne Bertrand
Chicago
Agree
4
Bio/Vote History
Brunnermeier
Markus Brunnermeier
Princeton
Uncertain
3
Bio/Vote History
Chetty
Raj Chetty
Harvard Did Not Answer Bio/Vote History
Chevalier
Judith Chevalier
Yale
Strongly Agree
7
Bio/Vote History
Cutler
David Cutler
Harvard
Uncertain
1
Bio/Vote History
Deaton
Angus Deaton
Princeton
Strongly Agree
7
Bio/Vote History
Duffie
Darrell Duffie
Stanford
Agree
1
Bio/Vote History
Conditional on successful enforcement, a simple calculation shows a substantial impact, assuming the revenues are redistributed naturally.
Edlin
Aaron Edlin
Berkeley
Agree
3
Bio/Vote History
Eichengreen
Barry Eichengreen
Berkeley
Agree
5
Bio/Vote History
Einav
Liran Einav
Stanford
Uncertain
1
Bio/Vote History
Fair
Ray Fair
Yale
Uncertain
5
Bio/Vote History
Finkelstein
Amy Finkelstein
MIT Did Not Answer Bio/Vote History
Goolsbee
Austan Goolsbee
Chicago
Strongly Agree
9
Bio/Vote History
Just go make a spreadsheet, plug in numbers and compound it
Greenstone
Michael Greenstone
University of Chicago
Agree
2
Bio/Vote History
i assume the question refers to pre-tax income.....
Hall
Robert Hall
Stanford
Uncertain
7
Bio/Vote History
Holmström
Bengt Holmström
MIT
Agree
5
Bio/Vote History
Hoxby
Caroline Hoxby
Stanford
No Opinion
Bio/Vote History
Bad Question! The condition "if successfully enforced" makes no sense given that wealth among the very top is inherently hard to tax.
Hoynes
Hilary Hoynes
Berkeley
Agree
7
Bio/Vote History
Judd
Kenneth Judd
Stanford
Agree
8
Bio/Vote History
Kaplan
Steven Kaplan
Chicago Booth
Strongly Disagree
10
Bio/Vote History
Pre-tax wealth inequality is driven by technology and globalization. Wealth taxes do not change those two forces.
Kashyap
Anil Kashyap
Chicago Booth
Agree
1
Bio/Vote History
Given that countries like France abandoned it makes me think this is unachievable, so this is like "assume a can opener" on a desert island
Klenow
Pete Klenow
Stanford
Agree
4
Bio/Vote History
Levin
Jonathan Levin
Stanford
Agree
4
Bio/Vote History
Maskin
Eric Maskin
Harvard Did Not Answer Bio/Vote History
Nordhaus
William Nordhaus
Yale
Agree
6
Bio/Vote History
Depends on design and enforcement. US has poor record at enforcing tax laws, particularly for non-wage income, so much uncertainty here.
Saez
Emmanuel Saez
Berkeley
Agree
10
Bio/Vote History
Wealth tax mechanically reduces returns to wealth at the top. Behavioral responses likely to magnify the effect. Effect builds up over time
Samuelson
Larry Samuelson
Yale
Agree
8
Bio/Vote History
If successful, taxation at rates of two or three percent, compounded over twenty years, would significantly diminish the taxed wealth.
Scheinkman
José Scheinkman
Columbia University
No Opinion
Bio/Vote History
Schmalensee
Richard Schmalensee
MIT
Agree
4
Bio/Vote History
Shapiro
Carl Shapiro
Berkeley
Agree
2
Bio/Vote History
Depends a lot on enforcement.
Shimer
Robert Shimer
University of Chicago
Agree
5
Bio/Vote History
It would also lead to much of the wealth moving offshore, despite provisions against that
Stock
James Stock
Harvard
Uncertain
3
Bio/Vote History
Thaler
Richard Thaler
Chicago Booth
Uncertain
1
Bio/Vote History
I don't know how we get to "successfully enforced". We can't collect the estate tax, why would we be able to enforce this?
Udry
Christopher Udry
Northwestern
Strongly Agree
9
Bio/Vote History

Question C Participant Responses

Participant University Vote Confidence Bio/Vote History
Acemoglu
Daron Acemoglu
MIT
Agree
6
Bio/Vote History
What would be most successful would be a combination of relatively high estate taxes combined with taxes on capital income.
Alesina
Alberto Alesina
Harvard
Strongly Agree
8
Bio/Vote History
Altonji
Joseph Altonji
Yale
No Opinion
Bio/Vote History
Auerbach
Alan Auerbach
Berkeley
Strongly Agree
7
Bio/Vote History
Autor
David Autor
MIT
Agree
5
Bio/Vote History
Baicker
Katherine Baicker
University of Chicago
Agree
3
Bio/Vote History
Banerjee
Abhijit Banerjee
MIT
Disagree
7
Bio/Vote History
Bertrand
Marianne Bertrand
Chicago
Disagree
1
Bio/Vote History
Brunnermeier
Markus Brunnermeier
Princeton
Agree
5
Bio/Vote History
Chetty
Raj Chetty
Harvard Did Not Answer Bio/Vote History
Chevalier
Judith Chevalier
Yale
Agree
9
Bio/Vote History
To use only income and capital gains taxes, a key policy lever would be eliminating the capital gains basis step up at death.
Cutler
David Cutler
Harvard
Disagree
1
Bio/Vote History
Deaton
Angus Deaton
Princeton
Disagree
5
Bio/Vote History
Duffie
Darrell Duffie
Stanford
Uncertain
1
Bio/Vote History
Edlin
Aaron Edlin
Berkeley
Disagree
6
Bio/Vote History
Eichengreen
Barry Eichengreen
Berkeley
Agree
5
Bio/Vote History
Einav
Liran Einav
Stanford
Disagree
1
Bio/Vote History
Fair
Ray Fair
Yale
Strongly Agree
5
Bio/Vote History
Finkelstein
Amy Finkelstein
MIT Did Not Answer Bio/Vote History
Goolsbee
Austan Goolsbee
Chicago
Agree
6
Bio/Vote History
Mostly but with some moderate differences.
Greenstone
Michael Greenstone
University of Chicago
Strongly Agree
4
Bio/Vote History
a reform of existing taxes to match wealth tax however would need to do something about the stepping up of cost basis for estate taxes
Hall
Robert Hall
Stanford
Agree
8
Bio/Vote History
We should focus on a progressive consumption tax structured as a value-added tax.
Holmström
Bengt Holmström
MIT
Uncertain
3
Bio/Vote History
Hoxby
Caroline Hoxby
Stanford
Agree
6
Bio/Vote History
Another bad question. This is a classic topic in fundamental tax reform, about which (I suspect) few Panel members have expertise.
Hoynes
Hilary Hoynes
Berkeley
Disagree
7
Bio/Vote History
Judd
Kenneth Judd
Stanford
Agree
8
Bio/Vote History
Kaplan
Steven Kaplan
Chicago Booth
Uncertain
1
Bio/Vote History
Kashyap
Anil Kashyap
Chicago Booth
No Opinion
Bio/Vote History
Klenow
Pete Klenow
Stanford
Disagree
3
Bio/Vote History
Levin
Jonathan Levin
Stanford
Uncertain
3
Bio/Vote History
Could be done with a capital gains tax, if assessed every year, rather than at time of sale.
Maskin
Eric Maskin
Harvard Did Not Answer Bio/Vote History
Nordhaus
William Nordhaus
Yale
Agree
9
Bio/Vote History
Start with enforcing the current laws. This would be highly progressive move and should be at top of tax agenda, way at top.
Saez
Emmanuel Saez
Berkeley
Disagree
10
Bio/Vote History
Estate and realized capital gains taxes come decades after wealth accumulation => wealth tax is a useful withholding tax back stop
Samuelson
Larry Samuelson
Yale
Agree
8
Bio/Vote History
Scheinkman
José Scheinkman
Columbia University
Uncertain
6
Bio/Vote History
Schmalensee
Richard Schmalensee
MIT
Uncertain
8
Bio/Vote History
Too broad. True of some goals, but not all plausible ones. Capital gains taxes and wealth taxes have a number of different effects.
Shapiro
Carl Shapiro
Berkeley
Uncertain
2
Bio/Vote History
Depends a lot on how effective those other taxes are, plus and they are not quite the same.
Shimer
Robert Shimer
University of Chicago
Agree
5
Bio/Vote History
This is similar to the estate tax, although the timing is different.
Stock
James Stock
Harvard
Disagree
3
Bio/Vote History
Thaler
Richard Thaler
Chicago Booth
Agree
1
Bio/Vote History
Yes, the estate tax is a sieve. Start with that? Get rid of step up to begin with.
Udry
Christopher Udry
Northwestern
Disagree
4
Bio/Vote History
Unless the changes in capital gains and inheritance taxes were radical, they can't match the time path of the wealth tax.