Diversification Simulator

The risk/return lesson ends on a cliffhanger: you can't escape risk, but you can be smarter about how much return you get for it. Diversification is how. By splitting money across assets whose returns don't move in perfect lockstep, you let one asset's bad year be cushioned by another's good one — so the blended portfolio's range of outcomes is narrower than its pieces would suggest, while its expected return is just the weighted average of the parts. That asymmetry (less risk, same return) is why diversification is called the only free lunch in investing. The simulator makes it visible by drawing two outcome cones at once: the diversified blend, and the wider cone that same blend would have if its assets moved in lockstep. The gap between them is the free lunch. Sliders for the stock/bond mix and for how correlated the two assets are show the two levers: the benefit is largest when the assets are least correlated, and it vanishes entirely when everything sits in one asset. The durable lessons: diversification reshapes the spread of outcomes without costing expected return; the benefit comes from low correlation, not from owning more things; and a concentrated bet — however good the asset — forfeits a protection that costs nothing to claim.

Free and interactive — no sign-up, nothing to install. Read the full lesson for the plain-language explanation.