The negotiations behind Aegis Media’s renewal and renovation deal at 150 East 42nd Street

Mr. Bernstein said Aegis, which in Greek mythology refers to Zeus’s shield, received concessions in the deal that were “similar” to what Wells Fargo received when it signed a 16-year lease for 275,000 square feet of office space at 150 East 42nd Street in April. Wells Fargo received 12 months of free rent and tenant improvements worth $75 a square foot in its deal. Mr. Bernstein would not comment further on Aegis’s concessions.

Mr. Wein said the firm is pleased it is staying in its current space.

“Our plan is to continue to grow, and at the moment we feel we have a competitive advantage in the areas of media and digital,” Mr. Wein, 36, whose company employs 16,500 people worldwide in 80 countries and boasts clients including Pfizer, Adidas and Home Depot. “So we intend to focus on that with more and more clients and grow significantly.”

Aegis—which, through a combination of companies, offers media planning, communications strategies and marketing analytics—has grown by up to 40 percent in the U.S. in the past two years, said Mr. Wein.

The company’s head count in its New York City office had also grown, from 400 employees to 500 in the past year alone.

Before signing the deal, Cassidy Turley and Aegis Media explored other spaces around Grand Central and Hudson Square while negotiating with CBRE and Hiro North American Properties to renovate both floors.

Aegis’s desire to renovate two floors of commercial office space added an interesting twist to lease negotiations, said Mr. Bernstein.

While the renovations themselves would be an expensive undertaking for Aegis, Mr. Bernstein knew the eventual value of the refurbished space would prove greater than the value of a new tenant coming in to replace Aegis in 2013.

“No landlord wants to lose a tenant like Aegis, for its scale, for its credit-worthiness,” said Mr. Bernstein.

Now with its new lease intact, Aegis wants its new office to showcase its three biggest companies in North America: media planning and buying company Carat; global communications firm Isobar; and digital marketing services firm iProspect. This will be the first time the trio of groups will operate under a single roof, said Mr. Wein.

“In the old days you can operate those businesses as silos,” he said. “But now all of them are kind of linked into one joined-up marketing strategy for our clients and therefore we actually bring them all to our clients together.”

The negotiations behind Aegis Media’s renewal and renovation deal at 150 East 42nd Street