Apartment Investment and Management Co. said it's ramping up its fight against short-term apartment rental company Airbnb.

Denver-based Aimco (NYSE: AIV) originally sued Airbnb in February for "illicit subletting" of apartments.

This week, Aimco ramped up its legal efforts, filing amended complaints in California and Florida, broadening its charges against Airbnb of San Francisco.

Aimco alleges that "a significant portion of Airbnb's business and revenues comes from its unauthorized short-term rentals of properties that Airbnb does not own and that Airbnb wrongfully profits from these transactions."

Read more at the Denver Business Journal: http://bit.ly/2rdr9Bb