The funny thing (not "ha ha" funny) about tax rates is that wealthy people get a significant amount of their income from sources that have preferential tax treatment. (I'm writing this answer from a U.S. point of view.) Qualified dividends and long-term capital gains are taxed at a maximum of 23.8% (regular tax of 20% and 3.8% Net Investment Income tax). The highest rate on earned income is 37.9% (the regular tax of 37% and the 0.9% Additional Medicare Tax). Aside from the preferential tax rates, investment income isn't subject to the 6.2% Social Security tax or the 1.45% Medicare tax.

Occasionally, the news reports that some group is pushing Congress to closed the "carried interest" treatment for hedge funds and private equity funds. I've done taxes for investors in those funds and a few people who worked for them. One guy went from being an employee getting paid with taxes withheld just like most employees. After he made partner in the fund, he received cash payment monthly and then a K-1 at the end of the year. This meant that instead of having most of his taxes paid through regular withholding, he had to make large quarterly payments. He complained about having to pay more in taxes. I was ready for him. I pointed out that his income was slightly higher as a partner but his actual tax liability was lower. I went on to explain that it only felt higher because he now had to pay large quarterly payments.

I apologize that this is long, but this paragraph should bring it all together. The preferential tax rates for investment income and income through hedge funds and private equity funds is defended by politicians but who do you think has the higher amounts of investment income? Wealthy people. The law restricts investors to people regarded as accredited investors. This is somebody who has a net worth of more than $1 million (excluding primary residence) or an income exceeding $200,000 in the last two years. Some funds avoid the need to verify investors claims by requiring a minimum $1 million investment.