Shares in China Mobile (Hong Kong) yesterday plunged to a 21-month low as disappointing interim results led analysts to downgrade earnings' forecasts. China Mobile plummeted as much as HK$2.50 to an intra-day low of HK$28.90 before recovering to HK$29.15 - its lowest price since November 1999. It was heavily traded, with HK$2.7 billion worth of shares changing hands, a third of yesterday's total market turnover. In the past two days, China Mobile has lost HK$5.65, or 16.2 per cent of its value, due to the poor interim results. Being the second-heaviest weighted stock on the benchmark Hang Seng Index, the fall in the mainland's dominant mobile operator shares helped drag the index down 77.63 points to 11,754.81. Other telecommunications stocks were also hit, with mainland rival China Unicom losing as much as 90 HK cents, or 7.9 per cent, to an intra-day low of HK$10.45. Hong Kong's telecoms giant Pacific Century CyberWorks eased two HK cents to close at HK$1.97. Most brokerage firms downgraded China Mobile's forecast earnings and target price on concerns of an accelerated drop in average revenue per user (ARPU) and slowing revenue growth. On Thursday, China Mobile reported a 58.3 per cent year-on-year rise in interim net profit to 13.8 billion yuan (about HK$12.97 billion), against consensus expectations of a 73 per cent growth. The main surprise of China Mobile's results was a 39.5 per cent year-on-year drop in ARPU, to 158 yuan. This was about 10 per cent below market expectations. Goldman Sachs, which has been bullish on the company, lowered China Mobile's ebitda (earnings before interest, taxes, depreciation and amortisation) by 8 per cent for the full year, and chopped the net profit forecast by 14 per cent to 69.99 billion yuan. The US brokerage has also downgraded China Mobile's one-year target price by 20 per cent, to HK$40. 'We believe China Mobile's share price will be volatile in the near term as investors set new forecasts and revise their valuation thinking,' it said. 'We therefore would not be aggressive long-term buyers in the near term.' Other leading brokerage houses, such as Merrill Lynch, Morgan Stanley, ING Barings and UBS Warburg have also downgraded China Mobile's earnings and target price. Morgan Stanley trimmed the one-year target price to HK$42.50 from HK$50, while UBS Warburg's was HK$28.50 from HK$31. BNP Paribas Peregrine was among the more bearish, revising down its valuation by 45 per cent to HK$21.30. CLSA Emerging Markets, though, lifted its valuation to HK$54.30 per share, on stronger subscriber growth.