Alasdair Taylor's Answer

Possibly, yes.

Companies are protected by the law of defamation (and also eg by the law of malicious falsehood).  Publication upon a website will usually constitute publication for the purposes of defamation.

Of course, it might be that the publication is not in fact defamatory, or that it is protected by the defence of truth.  A lawyer would need to discuss the details with you in order to make an informed judgment about this.