The energy business is far and away the leading reason why a growing number of large Texas firms have opened offices halfway around the world in the booming market of China.

“The reason we decided to open an office in Asia is we regard ourselves as the pre-eminent law firm in the world representing energy clients,” says Stuart Schaffer, a partner in Baker Botts, which opened an office in Hong Kong in 2005 and has asked the Beijing Municipal Justice Bureau for permission to open an office in Beijing.