Guam "corporation", "incorporated", "company", or "limited", or the abbreviation "corp.", "inc.", "co.", or "ltd.", or words or abbreviations of like import in another language; if the word "company" or its abbreviation is used, it shall not be immediately preceded by the word "and" or an abbreviation or symbol representing the word "and." Title 18, ยง 2110, Guam Code Annotated
On the other hand, if you are not responsible for its tax, then you should declare the equipment in Part III of the Business Property Statement (Equipment belonging to others). Where equipment is declared in Part III of the Business Property Statement, the Assessor will also send a Notice to File to the person reported as the equipment's actual owner.