How can you lose your claimed URL?
A) You remove all data feeds from your Merchant Center account
B) Another authorized owner of the website successfully verifies and claims your website URL
C) Your claimed URL authorization expired from Webmaster tools
D) Your website is updated but includes the same identifying meta tag or HTML file
The correct answer would be B, if another authorized owner of the website successfully verifies and claims your website URL. The good news is that if you lose your claimed URL, you will be notified via email. You are then able to verify and claim the URL at a higher level on the domain path. The other way this could happen is if you were to replace the current website URL in the website section of your Merchant Center account.