Never, she says, did Candib discuss the risks of holding the vast majority of her net worth in one stock with a high margin balance.

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The Federal Reserve Board requires long equity margin accounts maintain a balance of 50% equity, 50% margin debt.

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But this can be enough at the margin to tip the balance one way or the other.

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Either low interest rates have not got through to households or businesses because the banks need to make a higher margin on lending now to rebuild their balance sheets - or companies have plenty of money to invest, but they're too nervous about the future to do it.

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At the margin, it does make sense that buy-backs affect the balance of supply and demand.

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For most people, the value of their employment exceeds the value of their assets by a wide margin, and this asset has some special characteristics that make it differ from typical items on a balance sheet or brokerage statement.

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