Majority jackpot system

The majority jackpot system (MJS), also known as a majority-minority apportionment, is a mixed-member majoritarian and conditional voting rule. It produces subproportional representation by fixing the final apportionment for a party or alliance that wins a majority of the vote at some level (e.g. 55% of the seats). It differs from the similar majority bonus system in that the total number of seats is fixed, whereas the majority bonus assigns a fixed number of "bonus" seats to the majority party.

It is currently used in Armenia and San Marino, and was previously used in Italy from 2006 to 2013.

An example of a very small, almost insignificant majority jackpot type correction system is found in Germany's electoral system for the Bundestag. If a party receives more than half of the list votes, but does not receive more than half of total seats (for example, as a result of the apportionment formula), they receive as many seats as necessary, which are added to the size of the Bundestag.