What are the top 3 gaming companies?

Could you elaborate on which criteria are being used to determine the top 3 gaming companies? Are we looking at market capitalization, revenue, profitability, or perhaps a combination of these factors? Additionally, are we focusing on a specific region or is this a global ranking? Lastly, how does the rapidly evolving nature of the gaming industry affect the ranking and what changes, if any, can we expect in the NEAR future?