The falls in American share prices have been so sustained that the Fed felt it had to do something dramatic to change the pessimistic mood.

美国股价的下跌幅度非常大，美联储感到他们必须采取有力措施来改变悲观的情绪。

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The change is partly the result of the strengthening share prices of the almost 30 listed Tata companies.

BBC: India: Tata becomes India's wealthiest group

You see, I expect the prices of my shares to fluctuate in value throughout my ownership period, which in most cases is several years, and so I only consider selling my shares if there is a fundamental negative change in the company's prospects or share prices become irrationally overvalued.

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But there has been so little volatility in share prices in the past two years that any sharp change is unsettling.

ECONOMIST: Collywobbles