Estate Tax? Eh!!
I don't know much of Mr. Koch's finances. But billionnaire's don't pay such taxes, including estate taxes. There are many estate planning attorneys who will set up proper generational trusts and such so that you can avoid it too - provided you need it and can pay for it.
Those stupid tax laws are only for lowly humans like us. The libertarian overlords exist on a different plane, 'more equal than others' in Orwell's lingo, not subject to our laws!!
I don't think you can use trusts to avoid taxation on billions, but if you do LMK how. Obviously it could have been used to lock in a relatively paltry exemption. Perhaps there was a glitch in 2010 that made it temporarily possible.
Most billionaires use much more complicated mechanisms. Some are clearly abusive, but apparently defensible in court. Most of these mechanisms are not discussed in the public realm, just some leak out.
Mitt Romney had a 100mm Roth account. Think how hard it is to land with @5000/yr..
Trump Sr. gave a total of ~900MM to trump brothers and sisters as inheritance and gifts. Guess how much inheritance taxes they paid on that. It’s now, after the NYT investigative reporting on that, that NY has opened an investigation.
The ‘conservative’ billionaires DO NOT consider themselves subject to the same rules and laws as us (this is as opposed to the more ethical variety like Buffet/Gates etc who do actively and repeatedly bring attention to these absurdities).