The Contacts module has an enhanced search feature that allows you to create a list of Contacts based on information that is held on their Primary Company. To achieve this you should follow these steps;

• Go into the Contacts module.
• Click the + icon on the end of the Keyword Search panel to expand the search options.
  
• Click the Arrow icon to expand the Advanced Search options.
  
• Click the Company Information header to display the list of Company fields you can search on.
  
• Enter the search criteria in the Company fields as required.
• Select Search All to return your results.

Note : An example of where you might wish to use this feature would be creating a list of Contacts where the Primary Company is set as a Customer in the Company Type field.