http://www.blankrome.com/index.cfm?contentID=37&itemID=495 According to SEC Rule 10b-18: One Broker-dealer per Day: The company repurchasing shares may not use more than one broker or dealer to acquire the shares per each day. Timing of Purchase: A repurchase may not be the first trade of the day. Repurchases cannot be made in the last 10 minutes of the trading day, or 30 minutes if the company's ADTV is less than $1 million and has a public float of less than $150 million. These rules do not apply to over-the-counter securities, which are not traded on the NYSE or Nasdaq. Purchase Price: A repurchase may not be bid at a price higher than the highest independent bid or last price of the last trade. Volume: Repurchases per day may not exceed 25% of the average daily volume of the previous 4 calendar weeks. Block purchases not effected by a broker- dealer are excluded from this restriction 买了以后在10-K或10-Q的BALANCE SHEET 中的TREASURY STOCK中有显示,而且在NOTE里 有很详细的说明。