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处理隔夜跳空与日内贝塔估计

文章 Quant Q&A · 作者: silencer

总结

本文讨论如何根据15分钟的XLF相对SPY的收益率估计贝塔,数据跨度为数日,重点关注次日开盘时看似出现的跳跃。回答假设贝塔是根据收益率而非价格水平计算的,并指出,若回归仅使用日内收益率,隔夜跳空就不应纳入其中。使用收益率移动平均是平滑观测值的一种方法。

其他建议包括剔除收益率超过所选阈值的观测值,例如超过两个标准差的观测值,并比较不同采样间隔下的贝塔估计。较长的间隔可能平滑较小的跳跃,因此可以选择估计值最稳定且具有统计显著性的间隔。另一种方法是分别估计每天的贝塔,再对这些估计值取平均。这些是实用建议,并非经过检验的通用规则;本文没有指定正式的跳跃检测方法,也没有根据实证结果比较这些方法。

核心观点

  • 若根据日内收益率估计贝塔,隔夜开盘跳空不属于日内收益率序列。
  • 建议用移动平均平滑收益率,以此降低噪声。
  • 可以使用两个标准差之类的阈值剔除大幅收益率观测值。
  • 比较采样间隔有助于判断哪种间隔能得到更稳定且显著的贝塔估计。
  • 可以分别计算每日贝塔估计,再取平均。

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# How to account for jumps in intraday data when calculating beta?


# How to account for jumps in intraday data when calculating beta?












I am calculating betas on intraday trade data at 15-minute intervals. For simplicity sake, let's assume I am modeling

\begin{equation} Y = \beta * X + c \end{equation}

where $Y$ is the return of XLF and $X$ is the return of SPY.

If I want to run this on five days of intraday data, should I remove the jump that happens due to opening gaps on the next day?

How do you guys usually handle this jump in returns ?

## Answer by chrisaycock (score 6, accepted)

https://quant.stackexchange.com/a/2714

I assume you're using returns to compute beta, not the prices. And yes, remove the "jumps", though this should happen automatically since you're looking only at intraday returns. One final piece of advice: you'll get more meaningful results if you smooth the returns via a moving average.

## Answer by Suminda Sirinath S. Dharmasena (score 3)

https://quant.stackexchange.com/a/2715

In addition to the above I can suggest:

- ignore data point if returns are more than a certain threshold (2 s.d.)

- calculate at different sampling intervals and choose most stable beta with the best significance (certain longer intervals "smooth out" small to mid size jumps)

## Answer by LazyCat (score 1)

https://quant.stackexchange.com/a/2718

You can run the regression separately for 5 days, and average the betas you get for different days.

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