When you go through the central company 'gateway' it's there they can log ALL traffic; irrespective if it's over a 'secure' connection (https).
If the gateway is configured to, it can give you a self generated certificate; your browser sees it's an encrypted connection (& shows the padlock and "https" in the address bar).
Your traffic is decrypted at the gateway, logged, then re-encrypted, and sent to the Internet to it's destination, where that server 'sees' a valid secure connection (again, coming from the gateway), and then proceeds to behave as if it were only you involved.
All traffic goes to the gateway, encrypted, decrypted, logged, re-encrypted, and forwarded.
All this of course depends on whether or not Corporate has the gateway configured to have this behavior.
To ascertain your 'https' connection is not being proxied (and therefore potentially compromised a la 'man-in-the-middle' or corporate snooping):
double click the browser padlock indicating 'secure'> look @ the properties, and examine the 'chain of trust' or the 'certification path'; who's issuing the certificate, and so on. Untrusted issuing authorities, between the website and your machine would be an indication of some monkey business.
For example: a corporate environment or hotel, where the connection was using the gateway to issue certificates.