Speaking at the Morningstar Investment Conference, two experts shed light on exactly what trading costs are, and also shared tips on how to limit their drag on a portfolio’s returns. Dimensional Fund Advisors’ portfolio manager and trading expert Robert Deere discussed how DFA works to limit trading costs for its largely passive lineup, while BlackRock’s Jonathan Clark, head of the firm’s fundamental trading desk, provided perspective on managing trading costs for the firm’s actively managed equity offerings.