I mean, it’s in the name. The right to make copies. Not to be glib, but it really is
A copyright is a type of intellectual property that gives its owner the exclusive legal right to copy, distribute, adapt, display, and perform a creative work, usually for a limited time.
You may notice a conspicuous absence of control over how a copied work is used, short of distributing it. You can reencode it, compress it, decompress it, make a word cloud, statistically analyze its tone, anything you want as long as you’re not redistributing the work or an adaptation (which has a pretty limited meaning as well). “Personal use” and “fair use” are stipulations that weaken a copyright owner’s control over the work, not giving them new rights above and beyond copyright. And that’s a great thing. You get to do whatever you want with the things you own.
You don’t have a right to other people’s work. That’s what copyright enables. But that’s beside the point. The owner doesn’t get to say what you use a work for that they’ve distributed to you.
Because that’s not what copyright is for. It exists to give the creator exclusive rights over distribution. That’s it. So unless the company is planning to distribute the work and they obtained a copy willingly and legally distributed to them, then copyright is the wrong law to lean on.