contingent convertible instrument

177a financial instrument which meets the requirements for either:

1. (a) Additional Tier 1 instruments under article 52; or
2. (b) Tier 2 instruments under article 63, provided:
   1. (i) the provisions governing the instrument require that, upon the occurrence of a trigger event, the principal amount of the instrument be written down on a permanent or temporary basis or the instrument be converted to one or more common equity Tier 1 instruments; and
   2. (ii) the trigger mechanism in (i) is different from, or additional to, any discretionary mechanism for converting or writing down the principal amount of the instrument which is activated following a determination by the relevant authority that the issuer of the financial instrument (or its group, or any member of its group) is no longer viable, or will no longer be viable unless the relevant instrument is converted or written down;

in each case of the UK CRR230.