Ok genius - it's NOT David Simon, as you seem to suggest, who is cashing in SPG shares. Herbert Simon (David's uncle) and Mel Simon (died in 2009) started SPG many years ago. Herb is retired, getting old and extremely wealthy - so a notice that he is giving away shares isn't isn't exactly shocking news. Furthermore, it looks like the shares came out of a charitable trust.
Next time, why don't you try actually understanding the disclosure document before racing to post.
Giving away? This is an extremely illiquid position - malls are wastelands of retail losers. Go ask Filenes Basement to pay the rent - in their bankruptcy hearings. SPG $36 BILLION market cap is an outrage and it won't last. It WILL collapse, just like housing. Your customers, and their customers, are toast, accept it.