How do large firms find large commercial properties to flip?

[Patrick Philip]

Large firms will flip apartment complexes, large retail buildings, large office buildings, etc.

How do they find these for sale? They are not listed on the MLS and wholesalers that I've run into do not deal in properties this large.

http://www.crainsnewyork.com/article/20160131/REAL_ESTATE/160129828/the-real-estate-flipping-craze-shown-through-four-big-deals-in-brooklyn-and-manhattan