Nope it is not. Property tax does not take any gains into account - it's tax on full value (with possible exemptions) not gains, you pay the same regardless whether you bought it for $1 or $1M. Except of course in California where they have this weird scheme which led to the fact that my next door neighbor paid less than half of the property tax I did for pretty much identical house (because they bought it in the 80s) - which looks like negative tax on gains.