A new trend has been picking up steam in New York City: office-to-residential conversions. John Vavas, partner at law firm Polinselli's Real Estate practice in New York, has been active in this area representing lenders in these types of deals.

In the last six months, he estimates that he's helped close four or five transitions that involve transforming an office asset into residential use.

In one he represented Northwind Group in its recent $135 million loan to a joint venture between David Werner Real Estate Investments and Nathan Berman's Metro Loft to convert a portion of Pfizer's former headquarters at 235 East 42nd Street. The same JV was given a $75 million loan from Northwind for the other part of Pfizer's former headquarters over the summer. Collectively, both vacant office properties will be converted into 1,600 multifamily units, which is being called the "largest office to residential conversion in NYC history," according to Northwind.