冇錯,如果控制到成本嘅話你因子梗係越多越好,最好一個ETF有幾個因子exposure
Value stock唔一定幾時都同大市 correlation 咁高,睇市況,高通漲時期同埋growth stock爆破之後通常 correlation 都唔高
FTGC同DBC未太明,即係就咁long commodities futures? 如果係咁,咁最多算diversifier (尤其通漲嗰陣),唔可以話係positive expected return
gold 就我都當diversifier, 加少少都冇乜所謂
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