Two top American telecom firms -- AT&T(T) and Verizon(VZ) -- enjoyed a good year.
AT&T's brand value climbed by 15% to reach $89 billion, leading to its sixth place ranking. Verizon is close behind in seventh place.
Cheung said AT&T is trying to become more of a lifestyle brand for consumers, providing entertainment services in addition to typical telecom offerings.
However, the firm's shares have underperformed the overall market, and the company was kicked out of the Dow Jones industrial average earlier this year. Shares are down about 2% over the past 12 months.
First published May 27, 2015: 4:11 AM ET
Methodology: This 2015 BrandZ ranking of the most valuable brands in the world was carried out by brand consultancy Millward Brown, which is part of the advertising firm WPP. It calculates brand value by using in-depth financial data alongside interviews with over three million consumers from around the world.
