Quartz has a nice piece on UCO Bank “Meet the bank that wins only when Iran loses”. Due to the economic sanctions against Iran which prevented Indian importers of oil from paying Iran in dollars, a barter system was worked out under which the Indian importers deposit the purchase cost of the oil with UCO Bank, which is then used by Iran to make purchases from Indian exporters.
In this barter system, because there is a time lag between the deposit of the funds and its withdrawal, there are huge funds lying deposited with UCO Bank. The funds at present total nearly $3 Billion.
The result is that UCO Bank became one of the profitable PSU Banks with a low cost of capital.
However, all that may change no, with Indian importers of oil being permitted to pay Iran directly in foreign currency. Quartz quoted an analyst cautioning that heavy dependence on the Iran business is a major risk factor for UCO Bank.