Single non-transferable vote

SNTV is choose-one FPTP voting applied to the multi-winner context. It is a semi-proportional method.

SNTV passes a very weak form of Hagenbach-Bischoff-PSC (and Droop-PSC): if a group of voters of at least k HB quotas evenly distribute their votes between k candidates such that each candidate has at least one HB quota, then they can guarantee all of those k candidates either tie or win. This is because there can at most be ((number of winners) + 1) HB quotas in an election, so when k candidates have HB quotas, at most ((number of winners) - k + 1) candidates can also have HB quotas, resulting in a tie. As an example, if there are 3 seats and 100 voters, and 2 candidates each have an exact HB quota (25 votes), then either only one other candidate has more votes than the 2 (more than 25), meaning the 2 will be among the top 3 candidates (since if three candidates have over 75 votes together, then that means any other candidate must have fewer than 25 votes), or two other candidates also have 25 votes each, resulting in a tie.

If the k candidates instead each have a Droop quota, they are guaranteed to win, rather than only being guaranteed to either tie or win.

By analog to Duverger's law, SNTV in n-seat districts tends to produce (n+1)-party rule.