The 15-year lease and expansion would bring IPG’s total space across two Vornado buildings up to 745,000 square feet.

100 West 33rd Street (Credit: Arthur G. Cohen)

The multinational advertising and public relations company, along with its subsidiaries, already occupies 430,000 square feet at 100 West 33rd Street and 220,000 square feet of space at 909 Third Avenue, a source familiar with the pending deal said.

Agencies affiliated with IPG – including public relations firm Weber Shandwick – moved into 909 Third Avenue from 919 Third Avenue in October.

The company would occupy the entire fourth floor at 100 West 33^rd Street, previously home to Bank of America, for rents at or around $50 per square foot, beginning in late 2013, according to an initial report from Crain’s.

Scott Panzer of Jones Lang LaSalle represented the tenant, while in-house broker Glen Weiss represented the landlord.  Mr. Weiss and Mr. Panzer did not return calls and emails seeking comment.

The move comes after what has been a tumultuous year for IPG.  Last month, the company reported its third-quarter earnings had tumbled 66 percent, citing declines in U.S. revenue.

Earlier this month the company named new CEOs at Weber Shandwick and subsidiary McCann Worldgroup; and on Nov. 20 the company announced it had sold its remaining investment in Facebook for $95 million.

Back in July, Bloomberg News reported that IPG was being sued by a former executive demanding $381 million for his alleged role in an earlier selloff of Facebook stock.

Vornado is one of the largest owners of commercial real estate in the United States, with a portfolio of over 100 million square feet.