To view the list of Companies in your Account, click the icon at the upper right corner of your screen and then click Control Panel.

Go to the Company tab.  Here, you will see a list of companies registered in your account.

You can also see the list of companies in your account by hovering you mouse at the company logo in the upper left hand side of the page, and then switching companies by clicking the company you want to view. You can also access the Company page of the Control Panel by clicking Manage Companies.