I work with a company whose name is frequently reduced to an initialism (acronym). Let's say the name is "Cool Computer Systems" (CCS). I am engaged in an ongoing, bloody battle with the marketing department, wherein they insist the following apostrophe use is correct:
Buy CCS' New Product.
Reading that line brings visions of crying 4th grade teachers and librarians to mind. I am quite certain that it should be written:
Buy CCS's New Product.
The examples are in title case because the sentence is the subject line of an e-mail.
Their argument is that "Systems" is plural. I say that plurality doesn't matter, because "Systems" is part of the name. The name as a whole should be handled as a singular entity, because the company is, in fact, a single, legal entity. Thus, the possessive form should be written:
The Emperor's clothes
Cool Computer Systems's clothes