It may be bleak midwinter here in rural France, but the property market in the United States is still a bit feverish.

Remember that building that sold for $1.8 billion in New York recently? It was the most expensive single building ever sold in the city.

Well, we looked it up...

Its number is 666 5th Avenue. Already, we sense there is the Devil's hand in this thing. '666' is the 'mark of the beast' in the Old Testament. It prefigures the coming of the Antichrist, if we remember right. But what it marks in the property market is probably the very peak of the biggest property bubble in American history...and perhaps the peak of the whole worldwide property bubble. Which is to say, it might herald the coming of something big and bad.

You will know you have found the building when you walk along and come up to a Brooks Brothers store, on the ground floor. We used to do all our shopping there; it was known for a kind of waspy, out-of-fashion, high school history teacher look that we favored for years. (We have since moved on to an even more out-of-fashion style...we get most of our clothes from the local farm co-op.)

666 was purchased by the Kushner family. It appears that Mr. Charles Kushner, convicted of various financial crimes arising from his activities as a political fundraiser, decided to splash out when his time in the pokey was over. Now, he has got himself a trophy building...and has got everyone talking about him. Not only has he bought the most expensive building in the Big Apple; he's also shelled out three times as much for it as it sold for six years ago.

Either the man is a genius... or a fool. We will have to wait to find out for sure, but in the meantime we will do a little math. By our calculation, he paid $1,200 per square foot for the place. Let's see. In London, where we have an office, we pay about $50 per square foot per year. That is supposed to be a decent price...but about what you should expect to pay for prime office space in prime location in one of the world's prime cities.

But if you paid $1,200 to buy a square foot...how much would you have to rent it out for in order to make a profit? Well, if you apply the old rule -- you need to get 10% on your money just to cover your cost. That would imply a rental rate of $120 per foot squared. Then, in order to get a 5% return...the rent would have to be $180 per square foot. We don't know... can you get that sort of rent in New York?

Let's see...1,000 square feet for $180,000 per year..? Imagine a one-bedroom apartment renting for $15,000 per month.

No, dear reader...it is not very likely. Not even in Manhattan. Not even in a bubble.

Bill Bonner is the President of Agora Publishing.  For more on Bill Bonner, visit The Daily Reckoning.