International Boxing Organization

A second-tier sanctioning body founded in 1988, the IBO operates a fully computerised rating system based on results against ranked opposition. While not part of the "big four," the IBO is recognised by the British Boxing Board of Control and several other national federations, and many top fighters — including the Klitschko brothers — have collected the IBO strap as part of unifications.

Ranking methodology

Fully algorithmic computer-only rating system, with no Championships Committee subjectivity. The algorithm weights recent activity, opposition rating, and outcome (KO vs. decision). The IBO publicly publishes its rating formulas.

Notable controversies

• ▸Long-running criticism that the algorithm overweights inactive former champions, allowing them to remain artificially ranked.
• ▸Awarding "World Champion" status without formal recognition from the four-belt unified ladder, leading some fighters to be paid as IBO champions while not technically being among the top contenders in their division.