Now that Comcast has acquired a majority stake, NBC Universal has quietly signed a massive lease at Rockefeller Center with an NBC Trust and General Electric affiliate, public records show.

GE scooped up the real estate when it bought RCA to become NBC’s parent company in 1986, changing the red neon name in 1988.

The space itself was purchased by NBC for $440 million as part of the Rock Center bankruptcy bailout — spearheaded by current ownership led by Tishman Speyer.

The 1,417,777 square-foot lease runs for 10 years and has two five-year options.

The transaction breaks down to 755,602 square feet in the east building, aka 30 Rockefeller Center; 475,110 feet in the studio building, aka 49 W. 49th St.; and 187,065 feet in the west building, aka 1250 Ave. of the Americas.

All of the floors in these buildings are owned as individual office condominium units. The lease grants NBC Universal “a first offer option” to purchase any of the condos should the GE unit sell them.

An NBC Universal spokeswoman confirmed the lease. Jones Lang LaSalle Vice Chairman Scott Panzer repped NBC Universal/Comcast.

Meanwhile, a detailed scouring of the recent Rockefeller Center deal with accounting and consulting firm Deloitte for about 436,000 square feet found that it encompasses all of the condo units that are not already leased by NBCU.

That explains why some other 30 Rock tenants, like law firm Chadbourne & Parke, are unable to renew and are suddenly on the hunt.

That law firm, as The New York Observer reported, may be negotiating to become the anchor in Boston Properties’ stalled office development at 250 W. 55th St., where new building construction permits are being kept up-to-date.

A Chadbourne spokesman declined comment.

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In other Rock Center developments, DirecTV has nearly doubled its size, to 117,000 square feet, at One Rockefeller Center, which overlooks the skating rink on the mid-block street between W. 48th and 49th Streets.

The new lease for 52,828 square feet includes expanding into the entire second floor and taking over the newly vacated 18th floor — along with the 19th floor when it is vacated at the end of the year.

DirecTV, which has 28 million customers in the US and Latin America, will also be located on the third floor on a temporary basis, until the new space is built out.

Currently, DirecTV is on a portion of the second floor and the fifth through seventh floors.

Asking rent in the building is in the mid-$70s a foot.

“Global expansion has been a driver of companies like this one,” said Arthur Mirante of Cushman & Wakefield, who represented the tenant along with colleague Adam Rappaport.

Although there was no available space in the building, Rappaport said the C&W brokers were able to identify expansion opportunities through other C&W brokers.

Rock Center’s ownership, Tishman Speyer Properties, signed off on the expansion transaction.

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The law firm of Steptoe & Johnson will take over the entire 35th floor, or 31,000 square feet, at the Grace Building at 1114 Ave. of the Americas, overlooking Bryant Park.

The firm will move out of its current three floors at 750 Seventh Ave. sometime this summer.

Studley’s Daniel Horowitz and Jeffrey Peck represented the tenant, which will use some of the existing build-out and its tenant improvement package to customize and upgrade the space.

The Brookfield Office Properties ownership was repped in-house by Duncan M. McCuaig.

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Grubb & Ellis sales teams are bringing two downtown-ish properties to market.

The white apartment building at 344-46 W. 14th St. — just east of the Ninth Avenue/Hudson Street Meatpacking District demarcation line — will probably trade in the $25 million range.

The owner, Real Estate Equities Corp., has already installed Denim Habit in one of the two newly created retail spaces recaptured from residential.

Of the remaining 20 apartments in the six-story walkup, 10 are fair market, seven are stabilized, two are rent controlled and one is a super’s unit.

“Renovated apartments are flying out the door before the paint is dry,” said Neil Helman of G&E, whose teammates on the deal include Vin Carrega, Charles Kingsley and Yoav Oelsner.

Once the other retail space is leased, Helman said, “There will be a fabulous NOI (net operating income) at the end of the day.”

Helman, Kingsley and Oelsner are also marketing the retail condo in the base of the new 14-story Yves Condominium at 127 Seventh Ave. on the southeast corner of West 18th Street.

Ben Shaoul and Marc Ratner are the sponsors and sellers of the project, which features an entrance to the No. 1 line at its doorstep.

The 135 feet of retail frontage has floor-to-ceiling glass. The corner is leased to Shaun Osher‘s Core Residential Group, while the remainder of the 5,800 square feet is leased by the Bank of Smithtown, now owned by People’s United Bank.

The brokers believe the unit will sell in the $14 million range.

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Two buildings owned by affiliates of the NYSE Euronext were sold to hedge fund guru and commodity trader Michael Steinhardt of Steinhardt Management for a total of $65 million.

The old American Stock Exchange Building at 86 Trinity Place was sold for $17 million.

The 14-story former Curb Exchange building, built in 1931, also has the address of 125 Greenwich.

At the same time, the building next door — at 22 Thames St., aka 123 Greenwich — was sold for $48 million to the same entity.

The Curb Exchange building was closed at the end of 2008, when trading for the Amex was moved to the floor of the NYSE.

The new owners hope to turn the Trinity Place building into a retail complex, according to The Wall Street Journal, along with a 174-room boutique hotel. Meanwhile, they will tear down the 10-story Thames Street building and build a 60-story building that is likely to be luxury rentals, the newspaper reported on its Web site yesterday.

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Men’s fashion retailer Bonobos signed a three- year lease for a better- fitting full- floor loft of 10,000 square feet at 45 W. 25th St.

The company, which touts the fit of its trousers, was previously located in a smaller space at 59 W.19th St. before business, well, expanded.

Howard Rosen blum and Yvonne Chang of the Kaufman Organization rep resented the ten ant, while Alan Locker of Bonafide Estates repped the ownership, which had an asking rent of $30 per foot.

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Eric Negrin is joining Woody Heller‘s capital markets team at Studley.

Negrin was most recently with Paramount Group and cut his investment eyeteeth with Darcy Stacom at CB Richard Ellis, working on deals including sales of the GM building and Stuyvesant Town/Peter Cooper Village.

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We are very sad to report yesterday’s passing of Nicolas LaPorte, 61, executive director of the Associated Owners & Builders.

Sincere condolences to Nick’s family.

Dan Margulies, who some years ago was the executive director of CHIP, a rental owners group, will take over the helm at the ABO.