The best way to search for multiple companies is by using our all assignees search command (ALL_AN) which considers all the assignees used within our database.
As well as this, it is useful to remove these companies as inventors (using the search command IN) since the names of the companies may match up with the names of inventors.
Using these different elements, the best (general) search query that can be set up to search for multiple companies would be (ALL_AN:("Company 1" OR "Company 2" OR "Company 3" OR ......) ) NOT (IN:("Company 1" OR "Company 2" OR "Company 3" OR ......))
