How does the length of the time series affect the risk calculation approach? What if there is not sufficient data?

Where the time series covers more than 10 years, the manufacturer may proceed directly to the volatility calculation. Where the time series covers less than 10 years, a simulation approach must be used, based on historical values of either a reference asset or an appropriate benchmark. In all cases, the time series must not end more than 60 days before the calculation date.