Using Futures Positions to Adjust Portfolio Beta

Summary

The document asks how futures positions can change a portfolio’s beta, referring to a textbook explanation that reduces beta by cutting short futures contracts and raises it by adding long contracts. The underlying idea is that a futures position contributes market exposure: a short position offsets some of the portfolio’s market sensitivity, while reducing that short exposure leaves more of the original sensitivity in place. Adding long exposure increases the portfolio’s sensitivity further.

The question also asks whether a hedge calculation assumes an initial short position. The excerpt provides no answer, worked example, or empirical evidence, so it does not establish that short contracts are always the starting point. The direction and size of the adjustment depend on the portfolio’s existing beta, the futures contract’s exposure, and the desired target beta. It is a conceptual question about hedge direction, not a complete procedure for calculating contract counts.

Key ideas

• A short futures position can offset some of a portfolio’s market exposure.
• Reducing short contracts removes part of that offset and can increase portfolio beta relative to the hedged position.
• Adding long futures exposure can raise market sensitivity.
• Whether a hedge starts with short or long contracts depends on the portfolio exposure and target beta.
• The document frames the concept as a question and supplies no calculation example or empirical evidence.

Tags

# Why reduce number of short contracts to reduce beta, and take long positions to increase it?


# Why reduce number of short contracts to reduce beta, and take long positions to increase it?












My question is about chapter 3 in the ninth edition of "Options, futures and other derivatives" by John C. Hull, subchapter 5 under the heading "Changing the Beta of a Portfolio".

In the final paragraph, they explain how one can reduce the Beta of a portfolio by reducing the number of short contracts proportional to the reduction of the Beta (e.g. if the Beta is reduced by 0.5 times the Beta, then the amount of short contracts is reduced by 0.5 times the amount of short contracts), and by taking a long position using the same method, in order to increase the Beta.

I have some questions about this: first, how d you know that initially the portfolio holds shorted futures contracts? Is this always the case when calculating the amount of contracts required for a hedge/do they assume this in the chapter? And why does taking less short contracts reduce the Beta, but taking additional long contracts increase it? Is the first in order to reduce the total excess return and the second it in order to offset the sensitive change?

I believe my thinking is in the right direction but I tend to question it because I'm working with beginner's knowledge and understanding and I want to make sure I'm not mixing up or misunderstanding concepts, so far it's been hard to grasp.

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.