Here's the best tag to pull outstanding shares data in Intrinio's Excel add-in.
If you use "weightedavebasicdilutedsharesos" to pull outstanding shares into Excel, it may return zero for a substantial number of companies. Companies don't always report Weighted Basic & Diluted Shares Outstanding. Try using the "adjweightedavedilutedsharesos" data tag (companies frequently report this), which is also adjusted for stock splits. Here's an example:
=IntrinioFinancials("AMZN","calculations","2020","Q2","adjweightedavedilutedsharesos","A")
Replace the variables with cell references if you'd like.