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CBOE S&P 500 PutWrite Index (PUT)

SPX 1978.91 0.57
BXM 1096.40 1.35
BXY 1522.07 0.62
PUT 1463.33 0.00
CLL 653.27 0.00
Delayed Quotes

In June 2007 the Chicago Board Options Exchange (CBOE) announced that it is beginning to publish daily data on the value of the CBOE S&P 500 PutWrite Index (ticker symbol PUT). PUT is an award-winning benchmark index that measures the performance of a hypothetical portfolio that sells S&P 500 Index (SPX) put options against collateralized cash reserves held in a money market account. The daily historical data for the PUT Index now extends back to June 30, 1986.

The PUT strategy is designed to sell a sequence of one-month, at-the-money, S&P 500 Index puts and invest cash at one- and three-month Treasury Bill rates. The number of puts sold varies from month to month, but is limited so that the amount held in Treasury Bills can finance the maximum possible loss from final settlement of the SPX puts.

Study on Index Options Writing by Asset Consulting Group

In February 2012 the Asset Consulting Group published a six-page paper -- "An Analysis of Index Option Writing for Liquid Enhanced Risk-Adjusted Returns". Key findings of the paper include:

  • Total Growth. Total growth for indexes since mid-1986 was 1153% for PUT Index, 830% for BXM Index, 807% for S&P 500 Index, and 368% for CLL Index (Exhibits 2 and 6).
  • Lower Volatility. The PUT, BXM, and CLL indices all had volatility that was about 30 percent lower than the volatility of the S&P 500 Index (Exhibit 4).
  • Left-tail Risk. Over the past 25 years, the worst monthly loss for the S&P 500 Index was a decline of 21.5 percent, compared to a relatively modest 8.6-percent monthly decline for the CLL Index (Exhibit 8e).
  • Risk-adjusted Returns. One measure of risk-adjusted returns, the Sortino Ratio, was 0.90 for the PUT Index, 0.75 for BXY, 0.71 for BXM, 0.50 for S&P 500, and 0.31 for CLL Index (Exhibits 10 and 11). Please note that all the indexes had negative skewness.
  • Monthly Premium Income. The average for the gross monthly premiums collected by the BXM Index was 1.8 percent. The index options usually were richly priced (Exhibits 12 and 13).

For more information, please see the six-page paper and press release.

Links to More Information

The PUT logo is a service mark of CBOE. The methodology of the CBOE S&P 500 PutWrite Index is owned by CBOE and may be covered by one or more patents or pending patent applications. The CBOE S&P 500 PutWrite Index is designed to represent a proposed hypothetical short put strategy. Like many passive indexes, the PUT Index does not take into account significant factors such as transaction costs and taxes and, because of factors such as these, many or most investors should be expected to underperform passive indexes. In the construction of the hypothetical PUT index, the SPX puts are assumed to be written at a certain price on the third Friday of the month. However, there is no guarantee that all investors will be able to sell at this price, and investors attempting to replicate the PUT Index should discuss with their brokers possible timing and liquidity issues. Transaction costs for a put writing strategy such as the PUT could be significantly higher than transaction costs for a passive strategy of investing in Treasury Bills. Past performance does not guarantee future results. This website contains comparisons, assertions, and conclusions regarding the performance of index based on backtesting, i.e., calculations of how the index might have performed in the past if it had existed. Backtested performance information is purely hypothetical and is provided in this website solely for informational purposes. Backtested performance does not represent actual performance, and should not be interpreted as an indication of actual performance. Historical PUT daily data is provided for reference purposes only. Supporting documentation for claims, comparisons, recommendations, statistics or other technical data is available by calling 1-888-OPTIONS, sending an e-mail to, or by visiting
Options involve risk and are not suitable for all investors. Prior to buying or selling an option, a person must receive a copy of Characteristics and Risks of Standardized Options (ODD). Copies of the ODD are available from your broker, by calling 1-888-OPTIONS, or from The Options Clearing Corporation, One North Wacker Drive, Suite 500, Chicago, Illinois 60606. The information on this website is provided solely for general education and information purposes and therefore should not be considered complete, precise, or current. Many of the matters discussed are subject to detailed rules, regulations, and statutory provisions which should be referred to for additional detail and are subject to changes that may not be reflected in the website information. No statement within the website should be construed as a recommendation to buy or sell a security or to provide investment advice. The inclusion of non-CBOE advertisements on the website should not be construed as an endorsement or an indication of the value of any product, service, or website. The Terms and Conditions govern use of this website and use of this website will be deemed acceptance of those Terms and Conditions.

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