Systematic risk.

In plain English

Systematic risk is the exposure every asset in a market shares, driven by forces like interest rates, inflation, recessions, and policy shifts that move nearly everything at once. Because it hits broadly, adding more holdings does not make it go away. Spreading money across fifty stocks in the same market leaves the portfolio fully exposed to a market-wide decline. Investors are generally compensated for bearing this risk, which is the basis for expecting stocks to return more than cash over long stretches. The tools for managing it are asset allocation, hedging, and time, not diversification within a single asset class.

01Why it matters

It explains why a well diversified portfolio still falls hard in a broad selloff, and why the response is a different mix of asset types rather than more names.

02The math, step by step

A portfolio holds 60 different stocks. A market-wide decline of 20 percent takes the portfolio down close to 20 percent regardless of the count. Adding a 61st stock changes almost nothing. Shifting 30 percent into bonds that fell only 3 percent would have cut the portfolio decline to about 15 percent.

Illustrative example. The amounts here are hypothetical, chosen to show how the math works, not real quoted rates or figures.

03What this is NOT

04Receipts

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