For the purposes of point (a) of Article 56, institutions shall calculate holdings of own Additional Tier 1 instruments on the basis of gross long positions subject to the following exceptions:

1. (a)

   institutions may calculate the amount of holdings of own Additional Tier 1 instruments on the basis of the net long position provided that both the following conditions are met:

   1. (i)

      the long and short positions are in the same underlying exposure and the short positions involve no counterparty risk;

   2. (ii)

      either both the long and the short positions are held in the trading book or both are held in the non-trading book;

2. (b)

   institutions shall determine the amount to be deducted for direct, indirect or synthetic holdings of index securities by calculating the underlying exposure to own Additional Tier 1 instruments in those indices;

3. (c)

   institutions may net gross long positions in own Additional Tier 1 instruments resulting from holdings of index securities against short positions in own Additional Tier 1 instruments resulting from short positions in the underlying indices, including where those short positions involve counterparty risk, provided that both the following conditions are met:

   1. (i)

      the long and short positions are in the same underlying indices;

   2. (ii)

      either both the long and the short positions are held in the trading book or both are held in the non-trading book;