(21)An issuer may allow a person discharging managerial responsibilities to proceed with immediate sales of its shares during a closed period under exceptional circumstances. The issuer's permission should be given on a case-by-case basis, and the first criterion should be that a person discharging managerial responsibilities has requested, and respectively obtained, prior to any trading, the issuer's permission to trade. To allow the issuer to assess the individual circumstances of each single case, that request should be reasoned and include an explanation of the transaction envisaged and description of the exceptional character of the circumstances.