Let's say you plan to retire soon (maybe in the next few years), and you plan to fund your retirement with the index funds you've been diligently investing in for many years. Would it be a good idea to do some capital gains harvesting (selling and then rebuying investments in your taxable brokerage accounts), in order to increase the cost basis?
If I understand correctly, National Health Insurance premiums are calculated based on your income for the year, including capital gains from selling stocks. However, Shakai Hoken (while working at a company) premiums are only calculated based on your salary. However, whether before or after retirement, the tax on the capital gains would be the same 20.315%.
Therefore, it sounds to me that it's optimal to do some capital gains harvesting right before retirement so that your health insurance premiums aren't impacted as much by the capital gains. Am I overlooking anything here?
by kitsunegi