If you are a 501 (c) (3) organization you can supply a copy of the
tax determination letter sent from IRS to your financial officer. The
990 form includes a grat deal of often otherwise confidential
information on budget. If the question is tax status, then the IRS
letter is enough. If the request is playing nosey Parker, then its up
to you to decide how much you wish to tell them and how and
negotiatiate an appropriate compromise. Otherwise, "Have your CEO
call my CEO an do lunch!"