What is a Buy Back?

As the name suggests, it is a process by which a company can buy back its shares from shareholders. A company may buy back its shares in various ways: from existing shareholders on a proportionate basis; through a tender offer from open market; through a book-building process; from the Stock Exchange; or from odd lot holders.
A company cannot buy back through negotiated deals on or off the Stock Exchange, through spot transactions or through any private arrangement. Clearing and Settlement