Indian Overseas Bank (IOB) is a major public sector bank based in Chennai (Madras), with about 3400 domestic branches, including 1150 branches in Tamil Nadu, 3 extension counters, and eight branches and offices overseas as of 31 October 2017. Indian Overseas Bank has an ISO certified in-house Information Technology department, which had developed the software that its branches used to provide online banking to customers earlier. The bank has achieved 100% networking status as well as 100% CBS status for its branches. IOB has a network of about 3300 ATMs all over India. Indian Overseas Bank has branches in Singapore, Colombo, Seoul, and Bangkok. It has representative offices in Guangzhou, Vietnam, and Dubai. IOB also is part-owner of a joint-venture bank in Malaysia. Bank's equity shares are listed on Bombay Stock Exchange and the National Stock Exchange of India.