The Taxation of Concealed Offshore Wealth: Evidence from US Enforcement and Implications for Inequality

在美国、英国和一些欧洲国家，收入和财富不平等正在加剧。对日益加剧的不平等的担忧，导致公众对使用累进税收政策来限制不平等重新产生了兴趣。然而，在实践中，一个关键因素限制了现代政府对高收入、高财富个人征税的能力：利用离岸财富逃税。我们有什么证据表明，处于收入和财富分配顶端的个人赚取的收入和财富的很大一部分累积到隐藏的离岸账户，在那里通常是免税的。这个项目研究了利用离岸财富逃税造成的两个严重问题。第一个问题是一个直接的政策挑战：鉴于离岸财富的收入很难被发现，各国如何对其征税？第二个问题是一个带有下游政策后果的学术问题：在收入分配的顶端到底有多少人逃税，这对我们衡量不平等的程度有何影响？这项研究项目将使用美国国税局(IRS)的行政数据来回答这两个问题。美国是研究这些问题的理想环境，因为它是一个富裕的国家，而且美国最近针对离岸财富实施了越来越激进的政策。从2009年开始，美国使用了几乎所有可以利用的工具，包括诉讼、基于举报人数据的起诉，以及最重要的是通过新的立法。2012年开始实施的《外国账户税收合规法案》现在要求美国以外的金融机构向美国当局报告美国人在这些机构持有的财富和相关收入。考察这些政策的影响将有助于我们了解针对离岸财富的税收执法是否有效，通过实施这些政策产生的数据可以提供无与伦比的见解，了解离岸财富对于衡量不平等的重要性。项目的第一部分是使用数据来检验执法对逃税的影响。我们从非常简单的汇总数据分析开始，展示了离岸财富和收入的报告是如何随着时间的推移而演变的。初步结果表明，执法对报告产生了极大的影响，这在简单的汇总数据中是显而易见的。然后，我们将使用因果微观计量经济学研究设计，以了解汇总数据中的模式是否可归因于执法，并估计政策在几个维度上的总影响。我们将评估执法的整体影响如何因财富的位置、所有者在收入分配中的地位以及持有资产的方式而变化--直接或通过空壳公司。总而言之，这应该提供了对改革影响的详细概述，这是围绕这些执法政策正在进行的且有争议的辩论的重要投入。第二部分询问我们可以从离岸财富的新数据中了解到什么关于逃税和不平等的问题。大多数衡量不平等程度的指标，如收入占比最高的1%，都是使用个人所得税申报单中的数据进行估计的。如果人们通过隐瞒财富来逃避所得税，一些收入永远不会出现在纳税申报单上，从而偏离了对最高收入份额的估计。与此同时，通常用于研究逃税程度的随机审计几乎从未发现隐藏的离岸财富。我们将结合大量有关美国离岸逃税的数据，以及对随机抽样个人进行审计时的常规逃税数据。我们将估计整个收入和财富分配中的逃税程度，并估计修正了离岸逃税的最高收入和财富份额。这样的分布统计数据对于关于不平等的辩论至关重要。

Income and wealth inequality are on the rise in the US, the UK and some European countries. Concerns over growing inequality have led to renewed public interest in the use of progressive tax policy to curtail it. In practice, however, one key factor limits the ability of modern governments from taxing very high-income, high-wealth individuals: the use of offshore wealth to evade taxes. What evidence we have suggests that a significant share of the income and wealth earned by individuals at the top of the income and wealth distributions accrues to concealed offshore accounts, where it generally goes untaxed.This project studies two serious problems created by the use of offshore wealth to evade tax. The first problem is a direct policy challenge: how can countries tax income derived from offshore wealth, given that it is difficult to detect? The second problem is an academic problem with downstream policy consequences: just how much tax evasion is there at the top of the distribution, and how does this affect our measures of inequality?This research project will answer these two questions using administrative data from the United States Internal Revenue Service (IRS). The US is the ideal setting to study these questions because it is a wealthy country, and because the US recently implemented increasingly aggressive policies targeting offshore wealth. Starting in 2009, the US used virtually every tool at its disposal, including lawsuits, prosecutions based on data from whistleblowers, and, most importantly, the passage of new legislation. The Foreign Accounts Tax Compliance Act, implemented starting in 2012, now requires that financial institutions outside the US report to US authorities on Americans' wealth held at those institutions and the associated income. Examining the impact of these policies will help us understand whether tax enforcement targeting offshore wealth can be effective, and the data generated via the implementation of the policies can provide unparalleled insights on the importance of offshore wealth for the measurement of inequality.The first part of the project is to use data to examine the impact of enforcement on tax evasion. We begin with very simple aggregate data analysis, showing how the reporting of offshore wealth and income has evolved over time. Preliminary results suggest that enforcement had an extremely strong effect on reporting, which is visible in simple aggregate data. We will then use causal microeconometric research designs to understand whether patterns in aggregate data are attributable to enforcement, and to estimate the total impact of the policy along several dimensions. We will estimate how the overall impact of enforcement varies by the location of wealth, by owners' rank in the income distribution, and by the method of holding of assets - directly or through shell corporations. Together, this should provide a detailed overview of the impact of the reform, which is an important input into the ongoing and controversial debate over these enforcement policies.The second part asks what we can learn about tax evasion and inequality from new data on offshore wealth. Most measures of inequality, such as top 1% income shares, are estimated using data from individual income tax returns. If people evade income taxes by concealing their wealth, some income never appears on tax returns, biasing estimates of top income shares. Simultaneously, the random audits conventionally used for research on the extent of evasion virtually never detect concealed offshore wealth. We will combine a wide array data on offshore tax evasion in the US with conventional data on evasion from audits of a random sample of individuals. We will estimate the extent of evasion throughout the income and wealth distributions, and estimate top income and wealth shares that correct for offshore evasion. Such distributional statistics are vitally important for the debate over inequality.