Aurora Cannabis Inc (ACB)

[Scrapiron]

...when does the clock start for long term gains?...

How are stocks taxed?
There are two types of capital gains taxes on realized stock gains:
Short-term capital gains tax
Short-term capital gains tax is a tax on profits from the sale of an asset held for a year or less. Short-term capital gains tax rates are the same as your income tax bracket.
Long-term capital gains tax
Long-term capital gains tax is a tax on profits from the sale of an asset held for longer than a year. Long-term capital gains tax rates are 0%, 15% or 20%, depending on your taxable income and filing status.

Long-term capital gains tax rates are usually lower than those on short-term capital gains. That can mean paying lower taxes on stock sales.