Tribune Co. stock on Friday dropped the hardest in five years, after the Los Angeles Times reported that the planned $8 billion purchase by Sam Zell is in peril.

The Federal Communications Commission is considering possible changes in media-ownership regulations, which may cause the Tribune deal to not close on time, the Times stated.

“Tribune needs a waiver against owning a newspaper and TV station in the same market. (It owns KTLA and the Times). The FCC plans to vote on eliminating the ban on Dec. 18,” the Times article stated.