That's only true if you own single shares that you can't divide. If the market cap of the company is divided in enough shares that everyone can sell their porti

That's only true if you own single shares that you can't divide. If the market cap of the company is divided in enough shares that everyone can sell their portion of the buyback then it can be exactly like the dividend. And investors often directly reinvest the dividends so if you are holding an index fund that reinvests dividends, buybacks or dividends are the same except for any tax differences. If you're holding an index fund you also don't have the problem of the shares not being divisible, because someone else is managing that in aggregate for you.