ATLANTIC CITY, NJ—For the first time in a decade, the multifamily rental market “is starting to see a few dark clouds on the horizon,” as supply and demand move toward equilibrium, says Carl Goldberg, co-founder and former partner of Mack-Cali affiliate Roseland, who recently formed an investment partnership called Canoe Brook Management. “After ten successive years of rental growth in Hudson County, the primary luxury multifamily market in the state, we are seeing prices flattening.”