The term maxi originated with the International Offshore Rule (IOR) rating system, which in the 1970s and 1980s measured offshore racing yachts and applied a single-number rating to each boat. This number was approximately equal to the sailing waterline length in feet, plus or minus speed enhancing or reducing factors in the design. A yacht with a rating of 40 feet (12 m) was generally about 47 to 52 feet (14 to 16 m) in length overall. The IOR had upper and lower rating limits of 16 feet (4.9 m) and 70 feet (21 m), so a yacht designed and built to exceed the maximum limit of 70 feet (21 m) rating was known as a maxi.
For the 2009 Sydney to Hobart Yacht Race, the Cruising Yacht Club of Australia increased the IRC rating upper limit for length of hull from 98 ft to 100 ft, and most 98 ft yachts have been lengthened to this size. In order to achieve higher speeds, Maxi yachts were early adopters of modern materials and technologies such as carbonfiber, thermoformed sails, rotating wingmasts, water ballasts and canting keels. Previous smaller Maxi yachts are still raced with corrected time class victories in mind whilst the 72 ft “mini-maxi” yachts now have a class of their own.