What is 60/40, and why is it argued about?

Certain mixes get discussed so often they function as shorthand. The most famous is 60/40 — 60% equities, 40% bonds. Before going further, the framing that matters most in this whole course: these are reference points used to structure a debate, not recommendations. Nothing here says any reader should hold 60/40, or anything near it.

Why the reference points exist

A reference mix is useful for the same reason a standard candle is useful in astronomy — it gives everyone a fixed thing to measure against. When an institution says its policy portfolio "takes less equity risk than 60/40", the sentence carries information only because the listener knows the reference.

The commonly cited ones:

• 60/40 — the traditional balanced benchmark, in wide institutional use since the mid-20th century.
• All-equity (100/0) — the maximum-growth, maximum-drawdown endpoint.
• Risk parity — weights set so each class contributes equally to risk rather than to capital, which (given the variance arithmetic from Unit 1) means far less capital in equities and often leverage applied to bonds.
• The endowment model — heavy in illiquid private assets, viable only for investors with genuinely permanent capital.

The case for 60/40, stated fairly

• The equity sleeve supplies long-run growth; the bond sleeve supplies income and, historically, a cushion in equity sell-offs.
• Over the roughly two decades to 2021, US stocks and bonds were frequently negatively correlated, so the combination delivered a materially smoother path than either alone.
• It is cheap, transparent, and implementable by anyone.

The case against, stated just as fairly

• The correlation is not a law. The negative stock–bond correlation ran from roughly the late 1990s to 2021, and it was a regime, not a property of the two labels. What made it work was inflation being low and well anchored, so that growth shocks dominated: weak growth means lower earnings and easier policy at the same time, which sinks equities and lifts bonds. When inflation shocks dominate instead, the two move together — a rise in inflation cuts the real value of a bond's fixed cash flows and raises the discount rate applied to equities in the same breath. That was the pattern from the mid-1960s through the late 1990s, across the whole disinflation, and it is what returned in 2022: inflation surprised upwards, both sleeves fell, and a 60/40 lost roughly 16%. The right early-warning signal is therefore not the direction of inflation but its volatility — an illustrative reminder that the diversification came from a relationship, not from the labels.
• The risk split is lopsided. As computed earlier, roughly 95% of a 60/40's variance comes from the equity sleeve. Calling it "balanced" describes the capital, not the risk — which is precisely the objection risk-parity advocates raise.
• The starting conditions matter. Bonds bought at a 2% yield and bonds bought at a 6% yield offer very different future returns and very different cushions, and the reference mix is silent on this.
• It is a US-centric convention. Investors in other markets, with different currencies, tax systems and pension structures, have their own conventions for good reasons.

The counter-argument to the counter-argument

"60/40 is dead" has been declared repeatedly — after 2008, after 2013, after 2020, after 2022 — and the mix has continued to be the largest single reference in institutional practice. The steelman: a bad year is not evidence that a long-run structure failed, and the fact that a diversifier does not work in every single environment was never a claim anyone competent made about it.

What to take from the argument

Not a number. What the debate actually teaches is the set of questions any mix must answer: What is each sleeve for? What relationship is the diversification relying on? What happens if that relationship breaks? What are the current starting conditions? Those questions transfer to any allocation, including ones nobody has given a catchy name.

Try it now

1. Both sleeves are below. Navigate each to 2022 and Measure the calendar year. Construct the 60/40 result yourself with the weighted-average arithmetic and compare it to each sleeve alone.

2. Do the same for 2008. In that year, which sleeve provided the cushion, and by how much? Put the two years side by side: the same mix, the same two instruments, and a completely different experience.
3. Write one sentence naming the relationship the mix depends on, and one sentence describing what 2022 showed about it. Neither sentence should contain a recommendation.