(5)To avoid the risk of abusing the exemption for trading in own shares in buy-back programmes, it is important that this Regulation sets out restrictions with regard to the type of transactions an issuer can carry out during a buy-back programme and the timing of the trading in its own shares. Those restrictions should therefore prevent the selling of own shares by the issuer during the duration of a buy-back programme and take into account the possible existence of temporary prohibitions to trade within the issuer and the fact that an issuer may have legitimate reasons to delay public disclosure of inside information.