The Option to Repurchase Stock
把公司宣布的股票回购计划看作一种交换期权，管理者可在股价被低估时执行回购，否则放弃，从而为长期股东创造价值。
Companies often announce their intention to reacquire share via open market transactions. However, these programs are not firm commitments. By design, they provide managers the flexibility to forego repurchasing stock. Managers concerned with maximizing the wealth of long-term stockholders will tend to buy back share when they view their stock as undervalued and otherwise forego repurchasing shares. We value this inherent flexibility as an exchange option in which the market price of the stock is exchanged for the true value of the stock. Hence, the announcement of a repurchase expands the company's investment opportunity set. In essence, the programs authorize management to use the firm's resources along with their insider valuation of the firm to the benefit of long-term shareholders.