At my office, we have a 20 MB Excel file that is read-only. ~150 employees
use it, many at the same time.

Many employees are saying the sheet runs and operates slowly because of the
large number of people using the file. Could this be true? I thought a
read-only file would be opened on the user's own computer, so the speed and
performance of the sheet wouldn't be impacted by the number of users. But I
could definitely be wrong.

Can anyone tell me how the file opens? Does the large number of users
impact performance of the sheet?