What Does Style Box Mean?Created by Morningstar, a style box is designed to visually represent the investment characteristics of fixed-income (bond), domestic equity (stock) and international equity (stock) securities and their respective mutual funds. A style box is a valuable tool for investors to use to determine the asset allocation and risk-return structures of their portfolios and/or how a security fits into their investing criteria. There are slightly different style boxes used for equity and fixed-income funds.