Based on information from the New York's Department of State, Division of Corporations, Silk & Halpern Realty Associates is permanently closed.
They had partnered with ABS for the latter to manage 425 Madison, but that building no longer appears on ABS' website. The following does:
Land Assemblage
126,000 SF Developable
In partnership with Taconic Investment Partners
Location: New York, NY
https://absre.com/investments/land-assemblage/
I wonder if that's 425, which has about 125k sf.
In this market, it is a colossal waste not to partner with Durst and dramatically expand his site at 417 Madison.
Interestingly, however, there's nothing on ACRIS to shed light on this.