Similar mechanisms exist in the U.K. - entrepreneur’s relief/BADR allows you to pay a flat 10% on the full or partial sale of a business you founded, up to £1M - was £10M until 2020. You can of course do similar shenanigans with family to use their allowances too.
You can also of course emigrate to Portugal under the NHR scheme and between the fifth and seventh year sell whatever you fancy and not be liable for CGT anywhere.
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