Simons also played his chips, taking up positions in MasterCard and competitor Visa, while closing out his position in American Express.

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At some later date--either when you feel like closing out the position or when the lender wants the shares sent back--you have to buy some shares and replace what you borrowed.

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While we engaged in numerous partial sales before finally closing out that AAPL position in December 1999, our average gain topped 200%.

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