This will depending on your tax jurisdiction, but it's almost certainly a consequence of taxes: If the company buys its own shares, there are usually no taxes

This will depending on your tax jurisdiction, but it's almost certainly a consequence of taxes: If the company buys its own shares, there are usually no taxes on the purchase. If the company issues dividends, it has to pay taxes on dividends distributed. The shareholders may also have to pay a small amount of taxes on dividends they receive.