For a private company, the terms of the purchase contract will need to be authorised by a special resolution of the shareholders (at least 75% of the votes cast must be in favour of the resolution). If the company is purchasing shares out of capital (see question 8), an additional special resolution is required to approve this.
For a public company, purchases of shares through the market (e.g. the Stock Exchange) can be approved by an ordinary resolution of the shareholders (more than 50% of the votes cast must be in favour). The resolution must specify the maximum number of shares to be purchased, the minimum and maximum prices that can be paid, and how long the authorisation lasts (at most 18 months). If the shares are to be purchased 'off market' (for example, from one particular shareholder) a special resolution is required to approve the proposed contract between the company and the shareholder.
