Except with the consent of the CBB, if a person, together with any person acting in concert with him, holds shares carrying more than 50% of the voting rights of a company, neither that person nor any person acting in concert with him may, within 6 months of the closure of any previous offer made by him to the shareholders of that company which became or was declared wholly unconditional, make a second offer to any shareholder in that company, or acquire any interest in shares in that company, on more favourable terms than those made available under the previous offer. For this purpose the value of a securities exchange offer shall be calculated as at the date the offer closed. In addition, special deals with favourable conditions attached may not be entered into during this 6-month period.