"Three Billboards Outside Ebbing, Missouri" actors Sam Rockwell and Woody Harrelson are both up for the supporting Oscar. Although costars sharing categories was a nearly annual occurrence until the 1990s, it has happened less often since, and hardly ever with men.
6 — Years since Octavia Spencer and Jessica Chastain — the most recent nominees from the same film to vie in the same category — competed for the supporting actress statue for "The Help." Spencer won.
26 — Years since male costars were in the same race. In 1992, supporting nominees Harvey Keitel and Ben Kingsley, from "Bugsy," lost out to Jack Palance from "City Slickers."
5 films have yielded three nominees in a single category. The most recent was 1974's "The Godfather: Part II," for which Robert De Niro, Michael V. Gazzo and Lee Strasberg were up for supporting awards.
1 De Niro's subsequent Oscar is the only one won by a 3-in-1 nominee.
22 total Academy Awards have resulted from 141 performances by nominees pitted against costars. This is worse than straight 1-out-of-5 odds and lends credence to the "split the vote" theory.