Hello everyone,

I am working on a dataset containing a sample announcement dates (each standing for one acquisition made by one firm) and the firms that made the acquisition (identified by a unique identifier: scusip)

Now I need to assign all acquisitions to two subsamples. The subsamples are based on the number of other acquisitions made by the same firm that fall within any 5 year window around the announcement date of the focal acquisition.
What I am looking for is a way to find the maximum number of acquisitions that falls within any 5 year window of the focal acquisition. I do not need to know the exact window which yields the maximum number, only the number itself.

What I find difficult is that it can be any 5 year window.
I have not had any idea how to approach this so far, so all help is appreciated!

I attached an example of how my dataset looks like.

Thank you