President Biden proposes a new minimum tax on households worth more than $100 million as a part of the annual Budget. The tax that has been proposed is to ensure the very wealthiest Americans pay at least 20% in tax on their income. The tax proposal would affect fewer than 20,000 household. The plan would roughly generate $360 million in revenue over 10 years which the government could use to spend or increase the saving. Large amount of money in the new plan would come from taxes on unrealized gains built over many years and include much of the wealth of founders of large firms such as Amazon, Facebook (now Meta). Under the Biden Plan, if assets declined in value the future stream of payments would be adjusted downwards and if the value increases, it would lead to a larger stream of tax payments. Under current law capital gains are taxed only when the asset is sold and they are taxed at a lower rates than ordinary income, therefore it creates an incentive for people to hold appreciated assets until death.
https://www.wsj.com/articles/biden-to-propose-new-minimum-tax-on-wealthiest-americans-11648335232