Is New York’s Mark-to-Market Act Unconstitutionally Retroactive?

It is well known in tax literature that rudimentary tax planning strategies enable wealthy individuals to avoid state and federal income tax on much of their true economic income. Indeed, the existing income tax has been described as being effectively optional for those who derive their income chiefly from the ownership of assets rather than the provision of services. The reason is — except for a few relatively narrowly tailored deemed-realization rules — both state and federal income taxes rely on the realization principle. Under realization accounting, taxpayers generally do not owe tax on economic gains until they sell their appreciated assets. Moreover, this is so even when taxpayers fund lavish lifestyles by borrowing against their appreciated asset