Buying back shares

Benefits

If efficient market theory is correct, a company buying back its stock should have no effect at all on its stock price. If the market fairly prices a company's shares at $50/share, and the company buys back 100 shares for $5000, it now has $5000 less cash but there are 100 fewer shares outstanding; the net effect should be that the value per share is unchanged. However, buying back shares does improve certain per-share ratios, such as price/earnings (earnings per share is increased due to fewer shares outstanding), but that is only because valuing a company's shares according to those ratios is not accurate when a company is holding a lot of cash. If a company's shares are underpriced, then a company can benefit its other shareholders by buying back shares. If a company's shares are overpriced, then a company is actually hurting its remaining shareholders by buying back stock.

Incentives

One other reason for a company to buy back its own stock is to reward holders of stock options. Option holders are hurt by dividend payments, since, typically, they are not eligible to receive them. A share buyback program may increase the value of remaining shares (if the buyback is executed when shares are underpriced); if so, option holders benefit. A dividend payment short term always decreases the value of shares after the payment, so, on the day shares go ex-dividend, option holders always lose. Finally, if the sellers into a corporate buyback are actually the option holders themselves, they may directly benefit from temporarily unrealistically favorable pricing.

After buyback

The company can either retire the shares (however, retired shares are not listed as treasury stock on the company's financial statements) or hold the shares for later resale. Buying back stocks reduces the number of outstanding shares. To see this, note that accompanying the decrease in the number of shares outstanding is a reduction in company assets, in particular, cash assets, which are used to buy back shares.