About a year ago, there was speculation that Penn National might be interested in Cosmopolitan. (They're the ones who bought M Resort.) But no recent rumors.

This report (see link below) has interesting info about LV properties, but it is dated -- over 18 months old.
http://ktnv.images.worldnow.com/images/incoming/CBRE.pdf

Cosmo discussed on pg. 32, but prior to its opening.

There's an interesting property ownership map on pg. 18.
Cosmo is surrounded by MGM properties, and secondarily, by Harrah's across the street.
IF MGM had the $$, the geography would fit them best, as a defensive play.
Otherwise, a non-local operator, like Penn National or perhaps a private equity firm, could find the Cosmo's "externalities" attractive.

My guess, nothing happens until a stronger economy is evident.
Or ... at 1 million-to-1 odds, the Jockey Club owners buy it.