Here is a start. Not sure how Icahn is shorting the CMBS. Above my pay grade.AggiePeeps06 said:
Did we ever figure out a good way to short Commercial mortgages?
https://www.cnbc.com/2020/04/13/coronavirus-retail-hotel-borrowers-skip-mortgage-payments-trepp.html
https://www.investopedia.com/articles/etfs/081716/3-inverse-reit-etfs-betting-against-real-estate-rek-srs.asp