A friend forwarded a factor rotation pitch last night. Move into whichever style is working right now, it said, value, momentum, quality, whichever is hot. He asked me which factor he should be in today. So I pulled ten years of the leaderboard. Momentum finished first in 2020. The very next year it finished dead last. Value did the exact opposite, last in 2020, first in 2021. The whole table reshuffles, and last year's order barely whispers what this year holds.