A large buyback should push up stock prices. Documented retirement transactions or sale/redemption transactions that are recorded in a written contract are legally stronger and more flexible than those that are not documented. In the absence of documentation, the sale and redemption are considered two separate contracts. A buyback, also known as a share buyback, is when a company buys its own outstanding shares in order to reduce the number of shares available on the open market. Companies buy back shares for a number of reasons, for example. B in order to increase the value of the remaining available shares by reducing the offer or to prevent other shareholders from taking a majority stake.