Subcontractor question

I have a very good subcontractor who is doing software development for us with multiple team members. They have asked to see our insurance, which seems reasonable to me.

We have good insurance, but my partner is set against that saying that there is no reason for it, that our only obligation to him is to pay him. Furthermore, my partner says that his insurance should cover things if something goes south and he shouldn't be worried about ours.

My partner can't find any harm in sending it, but just doesn't think it is necessary. So, he is refusing to do so.

I would argue that him asking about our insurance is reasonable. If there is a problem, and we didn't have insurance, it could fall entirely on his company.

What do you all think? Is it reasonable and customary for a subcontractor to want to know about our insurance? And, is there any harm in doing so? For the life of me, I can't see why this would be an issue.