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. It has representative offices in Guangzhou, Vietnam, and Dubai. IOB also is part-owner of a joint-venture bank in Malaysia.