Mean reversion

PrepNuggets

LEVEL II

Mean reversion is a property of a time series where the values tend to move back towards a long-term average or “mean” over time. In autoregressive models, mean reversion is the assumption that the current value of a time series is a linear function of its past values and a white noise term, and that the past values of the time series are correlated to the current value. In other words, if the current value of the time series is above or below the long-term average, it will tend to move back towards the average over time. Mean reversion is often used in finance to model the behavior of financial instruments such as stocks or currencies.

To calculate the mean reverting level yt:

yt = b0 / (1-b1)

Synonyms:
Mean reverting level