Accountability score*: 72
Global 500 rank: 66
Sector: Computers and electronics
Vodafone moved from No. 3 to No. 1 this year, overtaking last year's leader BP. While Vodafone, Europe's largest cellular telecom company, doesn't have the environmental or even political challenges that a big oil company does, it does a superb job of questioning shareholders, employees, customers, and outside experts about how its services and infrastructure impedes - or might be able to help - economic development. That has resulted in programs like Mpesa, a pilot project that helps Africans do banking with their mobile phones. Vodafone has also changed the way it builds networks to give emergency health-care workers better access, and helps screen mobile video content for users with kids.