Colliers International completed a 220,000 s/f expansion and extension for AppNexus at 28 & 40 West 23rd Street. Michael Cohen, president of Colliers International Tri-State, represented the the owners. Mark Weiss and Rob Eisenberg, of Newmark Grubb Knight Frank, represented the tenant. "Watching AppNexus grow before our very eyes has been a wonderful experience," said Andrew Roos, vice chairman of Colliers International Tri-State, who leads the leasing efforts on behalf of the owners, which include the Cohen, Roos, and Carmel families. "We have gone to great lengths to create a campus-style complex that is appealing to digital, media, and fashion companies. There has been a synergistic relationship with AppNexus since they first moved into the complex, and we are thrilled to extend our partnership with them for at least the next ten years."