300 places or more
Names whose largest move between two consecutive years is at least 300 places, across a record held entirely inside the top 500.
Counted in places between two consecutive years only — never across a gap, where a change no single year saw would be reported, and never as a ratio, because a move from #1 to #2 is one place and not a doubling. Restricted to names whose every recorded year sits inside the top 500, with at least fifteen consecutive-year comparisons: a name ranked deep in a list published nearly 6,000 places down can move hundreds of places without much changing, so the figure would otherwise measure list depth rather than movement.
27 names, ordered by largest single-year move first.