After 45 years, more than 1,000 fights and some of the most lucrative and disputed matches of all time, HBO is throwing in the towel on professional boxing.

What started with a monumental upset seen by a relative handful of customers — George Foreman’s knockout of the heavyweight champion Joe Frazier in 1973 — will come to a close at the end of 2018. The network has no boxing broadcasts scheduled beyond a middleweight title fight at Madison Square Garden on Oct. 27.

Peter Nelson, the 37-year-old executive vice president of HBO Sports, announced Thursday morning, in a meeting with the HBO Boxing production staff, that the network was dropping boxing. The HBO Boxing staff includes the play-by-play announcer Jim Lampley, the analyst Max Kellerman, the ringside scorer Harold Lederman and the former boxing champions Andre Ward and Roy Jones Jr., who work for HBO as freelance commentators. Of the announcing staff, only Lampley is expected to remain with HBO.

“This is not a subjective decision,” Nelson said in a recent interview. “Our audience research informs us that boxing is no longer a determinant factor for subscribing to HBO.”