Technically it is not. Please review your knowledge of business contract law.

There is fine print associated with your orders from Mouser. In it, they declare that the transaction is considered proprietary, and you are not to indicate any details of it to anybody outside your company. You agreed to this when you placed your orders.

In general, you are not legally allowed to declare who your suppliers are, unless they give you permission. Likewise, your commercial customers usually do not want the world knowing that they buy things from you.

If I'm in competition with Larry's CB shop, and he's selling something for a whole lot less than I can sell it for, then I surely want to know where he gets it from. But Larry's got a good supplier, who keeps confidentiality agreements, so I am effectively on my own to figure out where to get that thing so cheaply.

Mouser is owned by TTI, and their policy is to never indicate who their customers are, unless the customer and TTI enter into a specific agreement for joint marketing. A company's "customer list" is considered one of the highest value proprietary items they have. Industrial spies seek to steal these lists.

So, no, it is not entirely up to them. You would have to specifically grant them permission to do so.

By business law, you are not "partners". The dictionary definition you provided clearly indicates an egalitarian relationship. You do not have one. They want money, you want parts - that's a one-way relationship, not a partnership.

I'm sure this all went over your head, though.