[isoskeles]

Is that how it works? Do they get to write off debts to assets of which they are still in possession, as if these are losses? Or are they writing off expenses for things they are not in possession of in any sense (e.g. employee salaries, goods sold)?

I am not an accountant, so I can't claim to fully understand what qualifies as a gain or loss, but my assumption has always been that the accounting rules are supposed to be sane and reflect the difference between these concepts (a real loss vs. going into debt).

[darawk]

They are probably depreciating the offices on a standard depreciation schedule. They are also writing off things like interest on their debt, etc..

Depreciating capital assets though is an extremely important part of the tax code. If you don't allow that businesses won't really be able to operate effectively.