In addition to the regular Hugo awards, beginning in 1996 Retrospective Hugo Awards, or "Retro Hugos", have been available to be awarded for years 50, 75, or 100 years prior in which no awards were given. To date, Retro Hugo awards have been awarded for 1939, 1941, 1943–1946, 1951, and 1954, but for each of those years, the Semiprozine category failed to receive enough nominating votes to form a ballot.
