Could Kamala Harris' proposal to tax unrealized capital gains be adopted in Canada?

financialpost.com:

U.S. Democratic presidential hopeful Kamala Harris has stirred controversy with a proposal to tax unrealizedcapital gains for the wealthiest Americans. The plan has come under fire for both political and practical reasons — and raised questions about whether the policy could make its way to Canada.

The Financial Post’s Barbara Shecter looks at the possibility of capital gains tax contagion.

Unrealized gains are earnings that accrue as a result of an increase in value on such assets as stocks or real estate holdings. Capital gains can be measured over a specific time period but are normally only taxable once the underlying asset is sold or disposed of in some other way, such as a charitable donation.

This plan would see such gains assessed annually, even if the asset in question isn’t sold by the investor or owner. The proposal, first laid out by U.S. President Joe Biden in March, indicated that such taxes would be treated as prepayments against future realized capital gains to avoid taxing the same amount of gain twice. The taxes could be paid in annual installments over a specified number of years. Under a complicated formula, some refunds would be provided in cases where there are subsequent losses or gifting of assets. This would only be the case if the prepayment amount exceeded the long-term capital gains rate times the taxpayer’s unrealized gains. However, refund amounts would first have to be put toward any remaining installment payments on previous unrealized gains before being refundable in cash.

So far it looks like individuals with a net worth (assets minus any liabilities) of $100 million or more. The proposal would impose a minimum tax of 25 per cent on total income for such individuals, “inclusive of