In the truest spirit of a financial planning niche, Justin Green is going with what he loves. Green, 29, is the founder of AssistFP, a Marlborough, Massachusetts-based financial advisory practice serving fitness-training entrepreneurs, many of whom have evolved into online ...

In some respects, David Foster has been living his advisory niche for most of his life. But it wasn’t until about three years ago that he realized he could incorporate his passion for philanthropy into his financial advisory practice. The ...