Why Index Options See More Put Activity Than Single-Stock Options
Summary
The discussion asks why index and ETF options can show greater put than call volume, while single-stock options do not exhibit the same pattern. The questioner reports spot checks on major indexes and stocks but does not provide a broader dataset or a formal test. The replies offer several possible explanations centered on how investors use options.
Investors may buy index puts to insure portfolios against broad market losses, and mutual funds can use such puts to hedge cash holdings. Downside protection may be especially valuable because market-wide distress affects many holdings at once. The discussion also invokes loss aversion and the pricing of options that pay off during macroeconomic crises. Single-stock options may be less useful as a signal or hedge for the overall economy; call trading may also reflect covered-call income strategies. These are proposed mechanisms rather than proven causal findings, and the observed volume imbalance may vary by market, period, and how volume is measured.
Key ideas
- Index puts can hedge broad portfolios more directly than puts on individual companies.
- Portfolio insurance demand may contribute to higher index put activity.
- Downside aversion and the value of protection during economic distress may support demand for puts.
- Covered-call strategies and company-specific risk may help explain different trading patterns in single stocks.
- The explanations are hypotheses; the cited spot checks do not establish causation.
Tags
Full text
# Why are Index/ETF put option volumes generally higher than the call option volumes? # Why are Index/ETF put option volumes generally higher than the call option volumes? It seems like put options on Index/ETFs generally have 50% more volume than call options, in terms of notionals. We don't see the same put/call volume ratios in single stocks. Why is that the case? I have thsi question after reading this article: https://www.ft.com/content/75587aa6-1f1f-4e9d-b334-3ff866753fa2 I have validated by spot checking the put/call volume ratios on Bloomberg terminal for a few major indexes and major tickers. This is indeed true. But I don't have an explanation ## Answer by kurtosis (score 1) https://quant.stackexchange.com/a/57907 Investors buy (and hold) more puts and pay up more for them for a few reasons. First, people fear downside more than they like upside as shown by Kahneman and Tversky (1979, 1992). Second, people may not be able to recover easily (or at all) from downside in the macroeconomy. In classical finance terms, if we think crises are different from times of stable growth, put options allow you to trade a state variable on macroeconomic distress (which the ICAPM says should be priced since it is valuable). This is the whole point of the Bondarenko (2014) expensive put options literature. See Figure 1 in the Bondarenko paper to see that puts having larger trading volume (and open interest) than calls is not new. As for why this does not hold for single stock options: That is probably because an individual stock is an even noisier measure of the prospects for the macroeconomy. In fact, we see slightly more calls being traded. It could also arise from portfolio managers selling covered calls as an income-generating method which also conditionally rebalances their portfolios. ## Answer by Dhruv Mahajan (score 1) https://quant.stackexchange.com/a/58596 It can mostly be attributed to portfolio insurance. Many investors (even mutual funds) are allowed to buy puts to hedge their downside risk in cash positions. I think the fact that mutual funds would buy puts increases the volume of puts vs calls with all else being equal. Since mutual funds are mostly positively correlated to the market, it makes sense to buy insurance on the whole market instead of individual stocks. ## Answer by user42108 (score 0) https://quant.stackexchange.com/a/58708 Conventional wisdom is that clients buy puts on an index (e.g. SPX) to hedge their overall portfolio but buy calls on their single names and this explains differing p/c ratios for indices vs. single stocks.
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