It's a short term stupid OMG!!!! reaction to the Feds totally predictable announcement that interest rates would be rising, after an buying frenzy that drove GGP up from $20 to $23 when there was no change in consumer buying or GGP management that could justify such an increase.
If you aren't a day trader, and you're going to invest in a real estate related stock, you have to learn to ignore daily trading prices at volumes close to the average volume. They don't predict a stock's future performance. They don't correlate with its yield over time. What a day's closing price reflects is buy high-sell low sellers and day trader activity, within the small pool of stock that's held by private investors.
GGP has approx 1B shares outstanding, normal day trading volume is approx 4M, or 0.4% of the outstanding shares. 95.75% of GGPs stock is held by institutions and insiders. They rarely trade, and rarely make rash decisions about their investments. Ackman hasn't sold GGP stock yet, only options. Brookfield is holding fast.
Small investors could never purchase the total holdings of any one institutional investor. So pay attention to the actual trading _activities_ of large investors like Brookfield, and Ackman, not a specious calculation of their assets "worth" based on the trading behavior of small investors.
I am wondering if it has to do with the extra selling pressure from Blackstone exiting its GGP position. They really didn't state in the article whether they already exited its position or if they are still doing it. Any thoughts?