General Growth Properties bought the stock for $20.12 each vs its close yesterday of $20.83.
The deal comes after Bill Ackman's hedge fund sold 25M shares in the shopping-mall owner in September for $500M.
Ackman helped rescue General Growth in 2009 by persuading it to file for bankruptcy and then taking part in its subsequent restructure.
The investment has been one of Ackman's most profitable. In 2011, he told Bloomberg that it "turned $60M into $1.6B." (PR)