 Share buy-backs are more tax-efficient than dividends when the tax rate on capital gains is lower than the tax rate on dividends.The most common share repurchase method in the United States is the open-market stock repurchase, representing almost 95% of all repurchases.A firm will announce that it will repurchase some shares in the open market from time to time as market conditions dictate and maintains the option of deciding whether, when, and how much to repurchase.