In Europe they address it via a range of taxes, the most common one being wealth taxes. These are inefficient because they are a double tax and invariably countries use a multiple of exemptions to try and get around that issue. The end result is that not all the tax gets collected. In the US (which has a 40% estate duty for wealth over $5.4m) indicating a desire to act against concentration of wealth. Other ways to try and deal to it include capital gains tax, property taxes, stamp duty, estate duty and inheritance taxes. All of these solutions are poor cousins to simply plugging the hole as we propose.