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Wall Street Quant · Financial Models · question 105 of 155

How many options do you need to hedge a position in 1000 shares of a stock given a delta of the option of 0.75?

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To hedge a position in 1000 shares of a stock using options, you will need to consider the delta of the option. Delta is the rate of change of the option’s price with respect to the underlying stock’s price, and it can be used as a proxy for the number of shares an option contract represents.

In this case, the delta of the option is 0.75, which means that for each 1changeinthestocksprice, theoptionspricechangesby0.75.

You want to use options to hedge your position in the stock such that the change in the option’s price cancels out the change in the stock’s price. The total delta of your options position should be equal to the number of shares you are trying to hedge (in this case, 1000 shares).

To calculate how many option contracts you need, you can use the following formula:


$$\text{Number of Option Contracts} = \frac{\text{Number of Shares}}{\text{Option Delta} \times \text{Option Multiplier}}$$

In most cases, an option contract represents 100 shares, so the option multiplier is typically 100. Using the given delta of 0.75, the formula becomes:


$$\text{Number of Option Contracts} = \frac{1000}{0.75 \times 100}$$


$$\text{Number of Option Contracts} = \frac{1000}{75} = 13.\overline{3}$$

Since you cannot purchase a fraction of an option contract, you would need to round up or down to nearest whole number. In this case, rounding up to 14 option contracts would give you slightly more than the required total delta of 1000, while rounding down to 13 contracts would give you a total delta slightly less than 1000.

If you prefer a more conservative hedge, you can round up to 14 option contracts, which would give you a total delta of 1050. This creates a slightly over-hedged position, and you would profit from the option’s price change even if the stock’s price falls. Alternatively, rounding down to 13 option contracts would result in a total delta of 975, creating a slightly under-hedged position where the options would partially offset the stock’s price change but not completely.

Ultimately, the decision of whether to round up or down will depend on your risk tolerance and preferences.

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