模拟财富税
模拟财富税
2020年8月
一些政治家提议在收入和资本利得税之外引入财富税。让我们尝试模拟不同水平的财富税的效果，看看它们对创业创始人在实践中意味着什么。
假设你在二十多岁时创办了一家成功的创业公司，然后再生活60年。财富税会消耗你多少股票？
如果财富税适用于你所有的资产，很容易计算其效果。1%的财富税意味着你每年保留99%的股票。60年后，你剩下的股票比例将是.99^60，即.547。所以直接的1%财富税意味着政府在你一生中将拿走45%的股票。
（显然，失去股票并不意味着变得更贫穷，除非每股价值增长低于财富税税率。）
以下是政府在60年内以各种水平的财富税拿走的股票数量：
| 财富税 | 政府拿走 |
|---|---|
| 0.1% | 6% |
| 0.5% | 26% |
| 1.0% | 45% |
| 2.0% | 70% |
| 3.0% | 84% |
| 4.0% | 91% |
| 5.0% | 95% |
财富税通常有一个开始适用的门槛。高门槛会有多大差异？为了模拟这一点，我们需要对你的股票初始价值和增长率做一些假设。
假设你的股票最初价值200万美元，公司的轨迹如下：你的股票价值在2年内增长3倍，然后在2年内增长2倍，然后在2年内增长50%，之后你只获得典型的上市公司增长率，我们称之为8%。[1] 假设财富税门槛是5000万美元。现在政府拿走多少股票？
| 财富税 | 政府拿走 |
|---|---|
| 0.1% | 5% |
| 0.5% | 23% |
| 1.0% | 41% |
| 2.0% | 65% |
| 3.0% | 79% |
| 4.0% | 88% |
| 5.0% | 93% |
起初似乎令人惊讶的是，如此明显的小税率会产生如此戏剧性的效果。2%的财富税加上5000万美元的门槛拿走了成功创始人大约三分之二的股票。
财富税有如此戏剧性效果的原因是它们一次又一次地应用于相同的钱。收入税每年发生，但只适用于那一年的收入。而如果你在获得某些资产后生活60年，财富税将对相同的资产征税60次。财富税是复合的。
注释
[1] 在实践中，最终这8%的一部分会以股息形式出现，股息在发放时作为收入征税，所以这个模型实际上代表了创始人最乐观的情况。
Modeling a Wealth Tax
August 2020
Some politicians are proposing to introduce wealth taxes in addition to income and capital gains taxes. Let’s try modeling the effects of various levels of wealth tax to see what they would mean in practice for a startup founder.
Suppose you start a successful startup in your twenties, and then live for another 60 years. How much of your stock will a wealth tax consume?
If the wealth tax applies to all your assets, it’s easy to calculate its effect. A wealth tax of 1% means you get to keep 99% of your stock each year. After 60 years the proportion of stock you’ll have left will be .99^60, or .547. So a straight 1% wealth tax means the government will over the course of your life take 45% of your stock.
(Losing shares does not, obviously, mean becoming net poorer unless the value per share is increasing by less than the wealth tax rate.)
Here’s how much stock the government would take over 60 years at various levels of wealth tax:
| wealth tax | government takes |
|---|---|
| 0.1% | 6% |
| 0.5% | 26% |
| 1.0% | 45% |
| 2.0% | 70% |
| 3.0% | 84% |
| 4.0% | 91% |
| 5.0% | 95% |
A wealth tax will usually have a threshold at which it starts. How much difference would a high threshold make? To model that, we need to make some assumptions about the initial value of your stock and the growth rate.
Suppose your stock is initially worth 50 million. How much stock does the government take now?
| wealth tax | government takes |
|---|---|
| 0.1% | 5% |
| 0.5% | 23% |
| 1.0% | 41% |
| 2.0% | 65% |
| 3.0% | 79% |
| 4.0% | 88% |
| 5.0% | 93% |
It may at first seem surprising that such apparently small tax rates produce such dramatic effects. A 2% wealth tax with a $50 million threshold takes about two thirds of a successful founder’s stock.
The reason wealth taxes have such dramatic effects is that they’re applied over and over to the same money. Income tax happens every year, but only to that year’s income. Whereas if you live for 60 years after acquiring some asset, a wealth tax will tax that same asset 60 times. A wealth tax compounds.
Note
[1] In practice, eventually some of this 8% would come in the form of dividends, which are taxed as income at issue, so this model actually represents the most optimistic case for the founder.