Put–call parity arbitrage

A stock is at $100 (no dividends), r=5%r=5\% continuous, T=1T=1 year. A $100-strike European call trades at $8 and the $100-strike put at $5. These quotes violate put–call parity, so a riskless arbitrage exists. What profit (in dollars, to two decimals) can you lock in per share, banked today?

Show hints (2)+
  1. Compare the synthetic forward C−PC-P with S−Ke−rTS-Ke^{-rT}.
  2. Arb =(S−Ke−rT)−(C−P)=(100−100e−0.05)−(8−5)=(S-Ke^{-rT})-(C-P)=(100-100e^{-0.05})-(8-5).

Answer

Reveal answer →

1.88 (± 0.02)

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