Shares of France's Unibail, says Corl, trade at a 16% discount to its real estate value.

FORBES: Old Europe's Realty Riches

Investor concerns that Unibail will mismanage malls outside of France are just "a lot of cross-border prejudice, " says Corl.

FORBES: Old Europe's Realty Riches

Aside from the economic growth story, limited acquisition opportunities in the U.S. put Simon at a disadvantage relative to other large international mall REITs such as Australian property operator Westfield Group and France-based Unibail-Rodamco, which are focused on creating value through renewal of property.

FORBES