China Mobile, which has 67 per cent of the mainland mobile-phone market, says the government may use regulatory measures to help its only serious rival, China Unicom, compete more effectively. Wang Jianzhou, the company chairman, said the government could adopt 'asymmetric regulations' in areas such as number portability, open roaming and network sharing to help smaller players, according to analysts who toured China Mobile's Sichuan and Henan province operations last week. Mr Wang said any such measures will have a neutral or slightly negative impact on China Mobile's operations. China Mobile, which uses the GSM standard for mobile telephony, had more than 282 million users as of August. China Unicom, whose systems use both the GSM and CDMA standards, had 137 million subscribers. In the mainland, mobile-phone users are required to change their numbers when changing service providers. This makes it difficult for rivals to shake customers loose once they have developed a relationship with a mobile-phone carrier. Although the government encourages the development of large companies in key industries such as telecommunications, earlier this month, in what might be a hint of things to come, it ordered China Mobile to stop offering fixed-line services in Shanghai. Analysts estimated that fixed-line services accounted for just 1 per cent of the company's sales. China Mobile shares have been among the best performers on the Hang Seng Index, gaining 50 per cent this year to date. They closed on Friday at HK$55.05. Unicom shares have risen 22 per cent this year. They last traded at HK$7.68.