Boutique investment managers really do outperform their larger peers, according to a recent study produced by Affiliated Managers Group (AMG), a West Palm Beach Florida-based firm that currently has around $776 billion of client assets under management.

AMG’s study found that not only did boutiques outperform non-boutiques consistently over the 20-year period that ended on 31 March 2018, they also outperformed primary investment indices on both a consistent and persistent basis.

The study examined the performance records of 1,300 individual investment firms that met AMG’s definition of a boutique and encapsulated ne...