A buy-back is not a sale

Two shareholders leave the same company on the same day, for the same money. One pays tax on a gain, the other on a distribution. The tax follows whoever wrote the cheque.

A co-shareholder buys you out — the money leaves their pocket and reaches you as sale proceeds. Capital, taxed where you are resident, and in a holding structure context exempt in many jurisdictions.

The company buys its own shares back — the money leaves the company's balance sheet. Most tax authorities look at that and see a distribution. Withheld at source, at a different rate, with a different treaty article deciding it.

Same exit, same money, two different outcomes.

Pay the exiting shareholder in assets instead of cash and you buy two more questions: what the assets are worth, and whether the company can prove it could spare them.