This document describes MASECO's RationalPortfolio approach to investing. It begins by explaining why their approach is different from more common approaches that promise market-beating returns or perfect timing of asset allocation shifts. MASECO's approach is based on empirical evidence and investment theory. They focus on minimizing costs, managing emotions, and keeping portfolio risk aligned through strategic rebalancing. The document then discusses how MASECO builds client portfolios using suitable asset classes and constructing a diversified "Return Engine" balanced by defensive assets. Key decisions in constructing the Return Engine include overseas diversification and including alternative assets classes.