RT Journal Article SR Electronic T1 The fundamental law of active management JF The Journal of Portfolio Management FD Institutional Investor Journals SP 30 OP 37 DO 10.3905/jpm.1989.409211 VO 15 IS 3 A1 Richard C. Grinold YR 1989 UL https://pm-research.com/content/15/3/30.abstract AB