If the participant was associated with the company through their team, you could use the following S-tag to display the company ID: 

[[E43:[[S334:fr_id]]:company-id:[[S334:team_id]]]]

However, if the participant is associated with the company as an individual, the company ID can't be rendered dynamically by an S-tag. Our Blackbaud developers might have a way of doing this by alternative means. You may be able to get some good web dev advice by posting in our Blackbaud Community, or you can set up a web dev consultation by contacting your account manager.