At the moment I am trying to calculate returns however I am attempting to calculate annual returns based on the accumulation of monthly returns. The issue is that that reports are released at different months in the year and I want to add a 4 month lag on top of that, which means that measurement could start in the year after. The data contains numerous different companies too which I dont want results to run between. As a result, my idea is to create a lag that varies by lag length based on the month in which the annual report is released + 4 months. I am unsure if this is possible but who better to ask than Statalist!

I have variables for month of financial year end (fyr), financial year (fyear), returns (ret), company identifying code (permno) and most likely any other variables which could possible be needed.