Waterton has agreed to buy North Harbor Tower from Crescent Heights in what may be the biggest downtown apartment trade in two years, Crain's Chicago Business reports. The sales price was undisclosed.

Crescent Heights paid $237M for the 600-unit Lakeshore East apartment tower in May 2016, the second-biggest apartment sale of that year. At the time, Crescent Heights viewed North Harbor Tower as a prime value-add opportunity near Millennium Park. The previous owner, the Florida State Board of Transportation, rehabbed 226 apartments.

The sale price, once known, will give investors an indication of where the downtown multifamily market is headed after a record-setting 2016 in deal volume. Rising interest rates, investor concerns about overbuilding and flat rent growth have led some owners to refinance their assets and pull money out of their buildings.

Crescent Heights has signaled in recent months it is looking to be a seller. After amassing a portfolio of 2,200 downtown apartments, the firm retained HFF to market The Lex, a 332-unit apartment tower near McCormick Place, to prospective buyers. Last month, Crescent Heights agreed to sell the Park Michigan, a 344-unit high-rise in the South Loop, to Horizon Realty for $90M.

Chicago-based Waterton recently closed on a $920M fund, its biggest ever, and is looking to acquire up to $2.5M worth of apartments through 2020.