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Stocks have two key differences with bonds:
- They pay dividends that vary over time as conditions change (no fixed coupons);
- They do not have a finite terminal date (no maturity).
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Let’s price a stock by arbitrage, assuming the investor can opt between a 1y bond or buying stocks
1+i1t+xs=$Qt$Dt+1e+$Qt+1e
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Reorganizing we have:
$Qt=(1+i1t+xs)$Dt+1e+(1+i1t+xs)$Qt+1e
$Qt = (1+i1t+xs)$Dt+1e+(1+i1t+xs)(1+i1t+1e+xs)$Dt+2e+(1+i1t+xs)(1+i1t+1e+xs)$Qt+2e= (1+i1t+xs)$Dt+1e+⋯+(1+i1t+xs)⋯(1+i1t+n−1e+xs)$Dt+ne+⋯
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Note also that we can derive this expression in real terms
Qt=(1+r1t+xs)Dt+1e+⋯+(1+r1t+xs)⋯(1+r1t+n−1e+xs)Dt+ne+⋯