LinkedIn offers 'update analytics' for company or brand pages, enabling admins to see metrics including impressions and clicks for each post made to that page. When viewing a page as an admin, click on 'Analytics' and then 'Updates':
I was looking at this recently to garner some statics on a particular post (or 'update') from just over three months ago. And I was surprised to discover that update analytics section only covered most recent 500 updates - 50 pages of 10, or 25 pages of 20 depending on the 'Show' setting.
This particular post was very slightly more than 500 updates ago (it's a busy page) so I was unable to find out anything from update analytics. Frustrating!
Instead, I thought I would tackle the problem another way - view the page as admin, then scroll right down until I found my post. At the bottom, I would be able to see the number of organic impressions plus some other information under the post's 'show stats' option. This is the kind of thing I mean:
So I started scrolling down. This took quite a while, as I had to scroll past 500 other posts. LinkedIn's infinite scroll also seemed a bit flaky, sometimes not wanting to load any new posts until I backed up a bit and scrolled down again. But eventually I made it to the 500th post... and the page didn't load anything else. LinkedIn brand and company pages show a maximum of 500 updates! Or to put it another way, the infinite scroll is not entirely infinite.
I don't know whether this means that older page content disappears entirely from LinkedIn - I suspect not, and would imagine that direct links to updates (such as this one https://www.linkedin.com/feed/update/urn:li:activity:6582557582844669953) will continue to work indefinitely. But it does mean that there is no way to get analytics on anything past the most recent 500 updates.
That might not be a problem if you are only posting to the page once a week (in fact it will last you nearly 10 years, during which time LinkedIn will no doubt have revamped pages more than once). But for marketers looking after busier pages, it's definitely an issue.