|If you don't have to do this very often, this brute force method should work:|
Let's assume your lists are in Column A and B, starting in Row 1.
In C1 enter this:
=IF(ISNA(MATCH(A1,B:B,0)), "Not Found", A1)
Drag it down to the bottom of your list.
If the name in Column A exists in Column B, then the name from A will show in Column C. If not, you'll get "Not Found".
You can then do a Copy...Paste Special...Values on Column C to eliminate the formulas and then Filter the list to show the unique company names.
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