Vodafone is selling its 3.2% stake in China Mobile for £4.3bn ($6.6bn) in cash as part of the mobile phone giant's strategy of exiting its smaller investments.It will return about 70% of the money to shareholders through share buybacks and use the rest to slim down its £33bn debt pile.All Vodafone's 643m China Mobile shares will be sold by an accelerated bookbuild run by Goldman Sachs, Morgan Stanley and UBS.The two phone giants will still cooperate in areas such as roaming, network roadmap development, multinational customers and green technology. "Today's transaction achieves a near doubling of Vodafone's original investment in China Mobile and combines our stated portfolio strategy with ongoing cooperation with China's leading telecommunications company," said Vodafone chief Vittorio Colao.