Using Index Futures as a Market Benchmark and Handling Expiry Rolls
Summary
The document explains how an index future or the underlying spot index can serve as the market return proxy when estimating stock betas. Spot returns are straightforward to calculate, and closing index values are described as reliable; opening and intraday values may be stale if constituent stocks have not traded recently. Futures prices provide a currently tradeable reference that incorporates current information.
To handle expiry, switch the return series to the next contract when leaving the expiring one. One approach calculates returns from each contract separately across the switch, accepting that the difference between nearby contracts is usually negligible for regression purposes. A roll can also be scheduled a few days before expiry or triggered by volume or open-interest crossovers. For daily close data, the response favors spot prices. It also notes alternatives such as broader European indices or a custom basket, while warning that broader futures may be less liquid. These are practical suggestions rather than a formal comparison of beta estimates.
Key ideas
- Spot index returns are easy to calculate, and closing values may be preferable for daily analysis.
- Futures offer a tradeable market proxy that reflects current information.
- A return series can switch from an expiring contract to the next contract, with a usually small discontinuity for regression.
- Roll timing can follow a calendar rule or changes in volume or open interest.
- A broader index or custom regional basket may be considered, subject to futures liquidity.
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# Why Index Futures can be used as a Market benchmark?
# Why Index Futures can be used as a Market benchmark?
I heard that we can use, say, Eurostoxx Futures as a benchmark to compute the beta of the index's components. Is this relevant? If so, how do we deal with the futures' expiry?
Thanks
## Answer by nbbo2 (score 2, accepted)
https://quant.stackexchange.com/a/57477
You can use either the spot value of the index (STXE) or the Futures Price for the current contract (FX*0) to compute the Market Return ($R_M$) on any day. The advantages and disadvantages are:
- The Spot price (which is computed from the prices of the underlying stocks) is easily available and computing returns is easy ($\frac{S_{t}-S_{t-1}}{S_{t-1}}$). The quality of the Closing spot price is very good, but the Open price may contain some stale data from the previous day and therefore should not be relied on, the intraday prices may also be somewhat questionable for the same reason (if some underlying stocks have not traded in a while).
- The Futures price has the advantage that it always represents a tradeable price and therefore always incorporates current information. There is no problem of data quality in this case, however as you point out contracts sometimes expire and are replaced by another contract. To deal with this is easy enough: on a normal day you use $\frac{F_{t}-F_{t-1}}{F_{t-1}}$ where $F$ is the current contract (for example Sep 2020). On the first day when you no longer wish to use the Sep contract, because it is about to expire, you compute the return as $\frac{G_{t}-G_{t-1}}{G_{t-1}}$ where $G$ is the next contract, in this case the Dec 2020 contract. The error introduced by this procedure is negligible for most purposes ($R_F \approx R_G$).
If you only need daily data at the close the Spot price method is probably best.
## Answer by kurtosis (score 2)
https://quant.stackexchange.com/a/57475
You may use EuroStoxx 50 futures as a market proxy for stocks in the index as well as other stocks. You could also use the STOXX Europe 600 (a better index, but with much lower futures liquidity) or build your own index from the DAX, CAC 40, FTSE 100, IBEX, MIB, AEX, BEL20, SMI, ATX, OMX, WIG, HEX, etc.
Handling futures expiry is usually done by switching to the next contract (like rolling a contract except rolling involves trading and thus fees). This can be done a few days before expiry or you can use other rules for doing the switch:when volume of one crosses the other and when open interest crosses are common rules. The difference between these rules will not likely impact your regression.Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.