来自《耶鲁大学开放课程：金融市场 第22集 第22集》

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  except that you understand
  除了我们发现的
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  that storage costs for stocks are negative
  股票的存储费用是负数
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  because they pay a dividend.
  这是因为我们能得到分红
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  So, all I've done is I've--
  我刚才说的是...
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  the way I wrote it before was
  上一讲我们用的公式是
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  P times one plus r plus s in the preceding lecture;
  P乘以1加上r加上s
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  now it's P times one plus r minus y
  而现在公式变为P乘以1加上r减去y
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  because s = -y.
  因为s等于负y
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  That's the fair value of a stock index futures.
  这就是股指期货公允价格的计算方法
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  Now, we said last time that
  我们刚才提到过
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  sometimes prices deviate from fair value--
  有时候期货价格不一定等于公允价格
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  or maybe they don't depending on how you define fair value.
  或者它们可能与你如何定义公允价格无关