Takasbank is a member of the Association of the National Numbering Agencies (ANNA). Acting as the National Numbering Agency of Turkey Takasbank is responsible for allocating ISIN codes for securities and other financial instruments in Turkey. ISIN (International Securities Identification Number) is an ISO standard (ISO 6166) that is used to uniquely identify securities. National Numbering Agencies (NNAs) coordinate their efforts through ANNA, which has 66 members worldwide as of June 2005.  ANNA also acts as the ISO maintenance agency for ISIN.

ANNA Service Bureau (ASB), which became operational in July 2001, is a central hub to receive and consolidate ISIN data from ANNA members and disseminate this information to the market via the Internet. ASB is operated by Standard & Poors (USA) and Telekurs (Switzerland). As of June 2005, the number of active ISIN records in the ASB database is 2.3 million and these ISINs are from over 190 countries.

Takasbank represents ANNA membership at the Advisory Board of ASB since 2001. In the last general meeting of ANNA held in Zurich, June 2005, Takasbank was unanimously re-elected to the Advisory Board of the ASB and further appointed as its chairman for 2005-2006.