Back on the market.

It looks like Billy Maklowe and wife Julie will not be getting a new home for the holidays. At least not at 950 Fifth Avenue. While the New York Post reported that real estate scion (son of Harry) was in contract to buy a 12-room co-op there this November, it looks like the deal has fallen apart.

At least a deal has fallen apart. The paper trail shows that the sprawling duplex, which first hit the market in July with Stribling brokers Cindy Kurtin and Jessica Vertullo Maher, went into contract in October. Only to re-emerge, back on the market, at the very end of November. Whether or not the rebuffed or regretful potential buyer was Mr. Macklowe, who helms William Macklowe Company, remains a mystery. Ms. Kurtin gave The Observer a "no comment" when we reached her on the phone.

What happened to Billy Macklowe's rumored contract?

The apartment was then, and is now, asking $27.5 million. Mr. Macklowe, according to the Post, was in contract for something below that. Could the building's board have nixed what it felt to be too low of a price?

As we noted before, the grand apartment would seem an ideal home base for a business mogul. Mr. Macklowe has been making more and more of a name for himself and a $27 million apartment on Fifth Avenue is a way to announce that one has arrived.

Besides, sister Elizabeth Macklowe lives a hop, skip and a jump away at 740 Park (At least for now. Ms. Macklowe and estranged husband Kent Swig’s apartment is said to be in the midst of foreclosure proceedings.)

Maybe the place was too grand? There's fancy and then there's fancy. This duplex is fancy, with wood burning fireplaces galore, parquet de Versailles floors, 11-foot ceilings, a windowed eat-in kitchen and park views. The banister to the second floor? Hand-crafted wrought iron and gilt.

kvelsey@observer.com

636 A of A. (Photo: PropertyShark)

Billy Macklowe has filled up the first building he bought without dad Harry.

Investment vehicle SecondMarket Holdings has taken about 50,000 square feet in floors three through six of 636 Avenue of the Americas in the flatiron. The 10-year lease brings the 90,000-square-foot building owned by  William Macklowe Company and Clarion Partners to 100 percent occupancy. Asking rents were between $55 and $60 per square foot.

The lease makes the firm the building's anchor tenant, and, therefore, ladies and gentlemen of New York, you now have the SecondMarket Building. The firm will ditch its current digs at 26 Broadway in early 2012.

Jim Wenk, Paul Formichelli, Dan Suozzi, and John Lewis of Jones Lang LaSalle represented SecondMarket. Mitchell Konsker, Matthew Astrachan, Jonathan Tootell and Matt Ginberg, also of JLL, represented the ownership.

The SecondMarket deal comes only a few months after Mr. Macklowe hired the Jones Lang LaSalle team led by Mr. Konsker to fill the building. Not bad.

pengel@observer.com

Mr. Konsker, who has assisted with leasing at many of Mr. Macklowe's other buildings, including 140 East 45^th Street and 340 Madison Avenue, will be overseeing the assignment alongside longtime partner Matthew Astrachan, vice president Jonathan Tootell and associate Matthew Ginberg.

Partnering with ING Clarion Partners, Mr. Macklowe has already begun a repositioning of the 90,000-square-foot building that will include restoration of the façade's historical architecture. When the renovations are complete, Mr. Konsker said, the Flatiron District building will stand as one of the city's most vaunted boutique office offerings.

"Ownership is committed to making a substantial investment in 636 Avenue of the Americas," he said. "The building will offer a tremendous opportunity for tenants looking for above-standard ceiling heights and creative space as well as the prominence of 13,000-square-foot full floors in a modern office building."

jsederstrom@observer.com