Paramount Group falls after Rithm Capital agrees to buy co for $1.6 bln

** Real estate investment trust Paramount Group's PGRE.N shares fall nearly 11% to about $6.5 in premarket trading

** Asset management company Rithm Capital agrees to buy PGRE for $1.6 billion in cash

** Rithm will acquire all of Paramount's outstanding shares of common stock for $6.60 per fully diluted share

** PGRE shares closed at $7.39 on Tuesday

** As of last close, PGRE shares up nearly 50% YTD