A few weeks ago, we posted an article about use of possessives with singular nouns. Here is some more advice about using possessives when dealing with brand or company names.
The names of many organizations and products contain words that could be considered either possessive or descriptive terms.
As a rule, use an apostrophe if the term is a singular possessive noun or an irregular plural noun.
- Harper's Bazaar
- Women's Wear Daily
- Children's Hospital
- Levi's jeans
- Reese's Pieces
Do not use an apostrophe if the term is a regular plural.
- American Bankers Association
- Chemical Workers Union
- U.S. Department of Veterans Affairs
- Ladies' Home Journal
- Reader's Digest
- Government Employees Insurance Company
In all cases, follow the organization's preference when known.
- Investor's Management Services, Inc.
- Lay's potato chips
- Folger's coffee
- Diners Club membership
- Thomas' English muffins
- Mrs. Paul's frozen foods
- Mrs. Fields cookies
- Taster's Choice
- Bakers Choice
- Lands' End catalog
When adding the sign of the possessive to a phrase that must be italicized or underlined, do not italicize or underline the possessive ending.
- Gone With The Wind's main characters
- The Wind in the Willows' author
Source: The Gregg Reference Manual