New York City’s luxury real estate market has a crazy list of loopholes for the wealthy: a tax abatement for affordable housing that somehow managed to benefit those living on Billionaires' Row; buyers who are permitted to mask their identities and potentially nefarious deeds behind anonymous LLCs; builders who have supersized skyscrapers through devious and bizarre designs, and as pointed out by a story in the Wall Street Journal on Thursday, owners who manage to pay relatively minuscule amounts of property tax.

A Central Park South penthouse that was recently purchased by billionaire hedge funder Ken Griffin for $238 million is worth only $9.4 million in the eyes of city tax assessors.

The report underscores the city’s convoluted and inequitable property tax system, which, among other oddities, elects to assess co-ops and condos as if they were rental properties. That means assessors base their estimate of the value of the 23,000-square foot apartment at 220 Central Park South on rental income generated by nearby apartments.

As a result, Griffin will have an annual tax bill that works out roughly $516,500. That is based on an effective tax rate, which is considered the best measure of tax liability, of 0.22 percent. The rate is lower than that of most outer borough homeowners. For example, homeowners in Staten Island can pay an effective tax rate as high as 1.0 percent.

Griffin’s tax liability even bests that of an unidentified buyer who bought a full-floor penthouse for $50.9 million in 2015. That person paid an effective tax rate of 0.42 percent, according to The Real Deal.

To put it another way, Griffin will pay the same effective tax rate paid by Mayor Bill de Blasio for his two homes in Park Slope, both valued at under $2 million.

According to a policy 2016 brief by the Citizens Budget Commission, co-ops and condos in New York City have an average effective tax rate of 0.86 percent.

“It is a crazy system,” Martha Stark, a former city finance commissioner who is now the policy director of Tax Equity Now, told the WSJ. “The true market value bears no relation to sales price, and nowhere is that truer than among high-value coops and condos.”

Tax Equity Now is suing the city over its property tax system, alleging that it unfairly works against renters and low-income and minority property owners.

The city is currently undergoing an effort to evaluate and come up with proposals to reform its property tax system. Last year, the de Blasio administration announced the creation of a Advisory Commission on Property Tax Reform which will set out a list of recommendations to be implemented at both the city and state level.

In the meantime, public furor over Griffin's exorbitant purchase is being leveraged to enact an previously floated policy. On Monday, the City Council revived its calls for pied-à-terre tax. Originally sponsored by State Senator Brad Hoylman in 2014, the state bill would levy annual fees on second homes worth $5 million and up. Under the proposed tax, Griffin could be asked to cough up $8,890,000 a year to the city.