Choose an unused helper column, say C, in C1 enter =COUNTIF(A:A,A1), then
apply autofilter in column C and click value 12.

regards,
Stefi

"Bram" wrote:

I have a large dataset of the monthly performance of certain companies.
example
a1:a12 contain January till december of company A
a13:a24 contain January till decmber of company B

Some companies only have data from March till december. How can I filter
these companies out of the dataset.

So I only want companies included that reported performance for a whole year

Thanks!!