Putin is the sort of the big boss, but I would guess that there’s like 10,000 people who surround him that are big recipients of these crimes. I would guess that a trillion dollars has been stolen from the state by Putin and these 10,000 people since he came to power. This is just such an extraordinary amount of money, and it’s so important for them not to have this game called over. Part of the problem with the Magnitsky Act is it does just that. I should point out that it doesn’t just seize the assets in the United States. It puts people’s names on the U.S. Treasury sanctions list. Once your name is on a Treasury sanctions list, you cannot open a bank account anywhere in the world. You can’t open a bank account in Peru; you can’t open one in Dubai. You can’t even open one in China because there’s no bank in the world that wants to be in violation of U.S. Treasury sanctions. You’re effectively a financial pariah from that moment forward, and no international bank, no international company, just about nobody will touch you as a legitimate person to do business with.
Source : http://www.slate.com/articles/news_and_politics/trumpcast/2017/07/why_does_putin_hate_the_magnitsky_act.html