Comparative performance assessments of the world’s leading energy companies.


How are the Top 100 rankings for companies calculated?

The ranking method used in The Energy Intelligence Top 100: Global NOC & IOC Rankings is a simple sum of the ordinal ranks of each company in six different operating categories: oil reserves, gas reserves, oil production, gas production, refinery distillation capacity and product sales. Each company is ranked against the entire group of companies surveyed for each metric. These six ranks are then summed, and the firms are ordered in the final standings according to this overall sum.

How often are The Energy Intelligence Top 100 Company rankings calculated?

The overall company rankings used in The Energy Intelligence Top 100: Global NOC & IOC Rankings are calculated on an annual basis, after Energy Intelligence has assessed and updated the entire data set and once all publicly-traded companies have reported annual operating results.

Where and how is data sourced?

Data is sourced from companies as disclosed in their annual reports, regulatory filings and other corporate communications. Where data is not readily available (as in the case of more opaque unlisted firms), we conduct primary research through proprietary in-house methodologies, which include utilizing company sources and information from Energy Intelligence’s news, analysis, data and research.

Why are some data points not available?

Energy Intelligence makes every effort to ensure that a comprehensive data set is collected for the entire suite of companies covered by The Energy Intelligence Top 100: Global NOC & IOC Rankings. However, certain individual parameters will not be reported, such as downstream data for a company that is purely involved in upstream activities. In some instances, where no data is available and Energy Intelligence experts deem that a reasonable estimate cannot be made, data is left out.

To whom do I report a data error or update?

While every effort is made to ensure that the data in The Energy Intelligence Top 100: Global NOC & IOC Rankings is accurate and up to date, there may be occasions when data may be incorrect. To report a data error or data update, please contact

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