The battle for New York City's most expensive penthouse is ON

Now that we have crossed the nine-figure threshold with the sale of a penthouse at One57 for $100.5 million, New York's luxury real estate developers are seeing how far they can push the price tags on their latest projects.

This week, two developers unveiled the floor plans for the top apartments in their new high-rises, and they are virtually guaranteed to set records.

Vornado Trust Realty is building a 69-story tower at 220 Central Park South, in the heart of Manhattan's "Billionaires' Row." While prices for the six penthouses have not yet been revealed, sources told The Real Deal that the most expensive one would "ask between $150 million and $175 million."

Meanwhile, Zeckendorf Development - the company behind behemoth 15 Central Park West - released the floorplans and price for the pinnacle apartment at 520 Park Avenue, the high-rise its building on Manhattan's east side. That penthouse, a triplex, will be listed at $130 million, The Real Deal reported.

And in February, the developers of another luxury tower at 550 Madison Avenue, the former Sony headquarters, announced that their penthouse would hit the market with a price tag of $150 million. That apartment, also a triplex, will encompass 21,500 square feet, according to The Real Deal.

Here's how the three new offerings (all still under construction) stack up:

550 Madison Avenue: $150 million, 21,500 square feet. Eight bedrooms, eight bathrooms, 10 half-baths.

520 Park Avenue: $130 million, 13,6500 square feet. Eight bedrooms, nine bathrooms, two half-baths.

220 Central Park South: "$150 to $175 million."

Somewhat less is known about the blockbuster penthouse at 220 Central Park South, since its floorplans have not yet been made public. We do know that the building will have six penthouses. The priciest unit currently on the market at 220 CPW is asking $60 million, according to The Real Deal. It has five bedrooms and is 6,591 square feet, so we can only imagine the specs for the best apartment in the building.

Given the red-hot nature of New York City's real estate market, it should be interesting to see who winds up living in these three penthouses.