如果係trend following 嘅話,我都有諗過alpha decay嘅問題,但既然trend following 歸根究底都係behaviour finance 嘅話應該啲alpha都難啲完全消失,最多係少咗
咁KMLM(pure 200 days MA trend following)的確16年之後表現遜色咗好多,我當真係alpha decay先啦而唔係市場結構有咩周期性嘅變化(反正我都唔識經濟學),咁起碼22年嗰陣佢都發揮到佢應有嘅用途。假設有樣嘢平時打橫行,極端市況嗰陣時可以同股票同債券uncorrelated兼多數會升,咁喺portfolio construction 嚟講已經好撚有用,更何況managed futures 唔係剩係得trend following