A lender that holds a mortgage on a building has its own interest in the insurance. Its protection survives even when the insured's own claim is denied, for example because the owner set the fire, as long as the mortgage holder meets its own duties.

California's standard fire policy in §2071 explains what happens next. If the insurer claims that no liability existed to the owner, it pays the mortgagee and is then subrogated to the mortgagee's rights to the extent of its payment. In other words, the insurer steps into the lender's shoes against the owner. The insurer may instead pay off the whole mortgage debt and take an assignment of it.

The mortgagee has a deadline too. If the insured fails to render proof of loss, the mortgagee must, upon notice, render proof of loss within 60 days after that notice.

A different number appears in the same section: the insurer may cancel the mortgagee's interest by giving the mortgagee 10 days' written notice. So 60 days is the mortgagee's proof-of-loss deadline, and 10 days is the cancellation notice to the mortgagee.