1. AT&T - the former SBC merged with AT&T creating the new AT&T (USA)

2. China Mobile - formerly China state-owned, now still state-controlled, one of two mobile phone monopolies in the entire China.

3. Vodafone - Britain's largest telecom operator.

4. Verizon Communications - US-based telecom company formed after a series of mergers.

5. Telefonica - Multinational company with stakes in Dpain, Latin America and Europe. Owns the O2 brand.

6. Deutsche Telekom - German telecom company, also owns t-mobile.

7. America Movil - Mexican operator controlled by the world's richest man - Carlos Slim.

8. NTT DoCoMo - One of Japan's telecom operators.

9. France Telecom - One of France's telecom companies.

10. Nippon Telegraph & Telephone - Japan's second largest telecom operator.