[_delirium]

That's in practice what happens, but it does make for a bit of strangeness from the perspective of fundamental valuations. At least in idealized theory, a stock is worth the time-discounted value of its future dividends plus any terminal liquidation payout (if the company eventually gets sold for cash). A share buyback increases the share of a company that a given stockholder owns, by getting rid of some of the other outstanding shares. That should make the share more valuable, because it's now entitled to a larger percentage of those future earnings... but raising the percentage of future earnings you're entitled to is only valuable if there are any! So either there have to eventually be some dividends or a cash sale, or else we have to abandon that view of valuation as having any tie to future earnings.

[yummyfajitas]

Share buybacks and dividends are mathematically equivalent:

1% share buyback when you own 100 shares (price=$100) -> $100 cash in your hands + 99 shares valued at $100/share.

1% of corporate value distributed as dividends -> $100 cash in your hands + 100 sharesvalued at $99 (since 1% of corporate value was given away).