Hello, I have panel data for 820 companies for 19 years i.e. 15580 observations (820*). I ran the following command after doing xtset company year:
. bysort Company: egen Max_Rev = max(Revenue)
(209 missing values generated)

I am not sure Stata shows 209 missing values generated. When I pulled out the data in excel, there are in fact 15000+ values in the column Max_Rev. Am I misunderstanding the meaning of "missing values generated"?