I'm doing a panel data analysis where the log of the freefloat number of outstanding shares is one of the explanatory variables, but it fails the Augmented Dickey Fuller and Person Phillips unit root tests. But intuitively I suspect it to be stationary but with structural breaks. (I know these unit root tests to be sensitive to breaks.)![nosfhl]
The image shows this variable for 108 stocks, and over a time-span of 15 years.
Could you say something useful about the nature of these timeseries?