Following the ECB decision establishing a secondary markets public sector asset purchase programme (PSPP) which provided for that the purchase of eligible marketable debt securities under the PSPP are subject to an initial issue share limit of 25% per international securities identification number (ISIN).

On 3 September 2015, the ECB decided in principle to increase the PSPP issue share limit from 25% to 33% per ISIN, subject to verification on a case-by-case basis that a holding of 33 % per ISIN would not lead the Eurosystem central banks to reach blocking minority holdings in orderly debt restructurings, and has therefore decided to amend Decision (EU) 2015/774 (ECB/2015/10) to reflect this.