Japan is proposing an enlargement of its tax base for the ultra-wealthy in a new groundbreaking policy in wealth management. It reflects a larger ongoing discussion about wealth inequality in the country. While details are still being dialed in, the government aims to capture a higher proportion of income from the supremely rich. The proposal is currently under negotiation with no set implementation date.

Japan is known for its high levels of wealth concentration. This move is seen as a balancing act by the Japanese government to tackle wealth inequality while sustaining its economy. There's a broad public endorsement but also some fear that it could discourage investment or trigger capital flight out of the country.

In comparison, wealth tax debates have also been a significant issue in the US and EU, particularly in light of increasing wealth disparity. However, unlike Japan, the US has not yet successfully implemented such a tax and EU nations have mixed approaches.