Why are the monthly index values for the current year subject to change?

Answer

Due to the inherent lag in financial reporting, financial statement data is not published until up to four quarters after the financial year end. Thus, the index results when they are first released are indicative only. Results for dates more than four quarters before the as-of date are based on realised financial statement data and are thus frozen with a 1-year lag.

This is noted as such on the Performance tab via the dotted line titled “Frozen”:

Whilst variance tends to be small given the precision and robustness of our model, larger changes in recent period can be attributed to the volatile macroeconomic environment. Our Research Institute has elaborated on some of the macroeconomic drivers in recent research papers, which you can find here.