Deductibility of Co-op Maintenance

Yes, that is correct. If you are a shareholder in a co-op that carries an underlying mortgage, you should receive a statement from the corporation's accountants in January which includes per share deductions for both mortgage interest and real estate taxes for the prior year.

I believe that's correct. You should confirm with the building's management company on this. If you're a coop owner the mgt co will send you a statement each year showing how much of your maintenance paid is tax-deductable.

OP here. Thanks to both of you.

correct, underlying mortgage interest is fully tax deductible, as is mortgage interest on your mortgage on the unit.