Indian Oil Corp (IOC) has been ranked as the number one oil trading company amongst national oil companies in the Asia Pacific region.The annual survey conducted by Singapore-based applied trading systems (ATS) ranked IOC the number one trading company ahead of Petronas of Malaysia, Sinopec of China, Hindustan Petroleum Corp (HPCL) of India and Emirates National Oil of United Arab Emirates, a company press release said.IOC has topped the list for the second year in succession, and the survey covered 79 major petroleum trading companies in the Asia Pacific region."Over the years, IOC has initiated series of measures to benchmark its trading systems with international best practices. In order to enhance the use of risk management tools to mitigate risks arising out of volatality in international oil prices, IOC commenced derivative trading for the first time in 2004," the release added.