What is the No-Brainer portfolio?

William Bernstein's equal four-way split — 25% each in the S&P 500, US small-caps, international stocks, and bonds — rebalanced yearly.

Is the No-Brainer portfolio good?

It is a solid, diversified, easy-to-run portfolio well suited to long-term investors. Its main risk is the 75% stock weight, which means large drawdowns in crashes.

Why include small-cap and international stocks?

They behave differently from US large-caps and have historically added return, so mixing them in reduces reliance on any single slice of the market.

Does William Bernstein's No-Brainer portfolio work?

By Jeffrey Lin · Published 2026-08-24 · Updated 2026-08-24

The No-Brainer portfolio, from neurologist-turned-author William Bernstein, is four equal 25% corners: US large-caps (S&P 500), US small-caps, international stocks, and bonds. It is deliberately simple — diversified enough to be sensible, easy enough to run forever without a second thought.

From May 1996 to Jul 2026, a yearly-rebalanced No-Brainer portfolio returned 7.9% per year with a maximum drawdown of -40.9% — versus 10.3% and -50.8% for S&P 500 (SPY) alone. It gave up some return for materially lower risk, producing a higher Sharpe ratio (0.69 vs 0.72). $10,000 grew to $100,388 (vs $192,480 in the S&P 500).

What's in it: the allocation

SPY25%
VB25%
VEA25%
BND25%

Growth of $10,000

Growth of a $10,000 investment, May 1996–Jul 2026. The No-Brainer line rises more slowly than the S&P 500 but with visibly shallower dips — the trade-off the strategy is designed to make.

What an investor actually experiences: drawdowns

Decline from the prior peak — the "underwater" curve.

A drawdown is the stretch of time when your account is worth less than it was, with no way to know when it will recover. No-Brainer's worst decline was a deep -40.9% — close to the S&P 500's -50.8%. How long the pain lasted matters just as much: it spent as long as 45 months (about 3.8 years) below a prior high, versus 74 months (6.2 years) for the S&P 500.

A fall of -40.9% is the kind that tests conviction. If you needed this money for a house, a child's tuition, or retirement during such a slump, you could be forced to sell near the bottom — which is why money you will need within a few years usually belongs somewhere less exposed than this.

Results

Statistic	S&P 500 (SPY)	No-Brainer
CAGR	10.3%	7.9%
Annualized volatility	15.3%	12.2%
Sharpe ratio	0.72	0.69
Sortino ratio	1.10	1.03
Max drawdown	-50.8%	-40.9%
Longest drawdown (months)	74	45
Growth of $10,000	$192,480	$100,388

Here is what those figures mean for a real saver. CAGR is the smoothed annual growth rate: at 7.9% a year, No-Brainer turned $10,000 into $100,388 over about 30 years, versus $192,480 for the S&P 500. Volatility (12.2% vs 15.3%) is how much the ride bounces from year to year. The Sharpe and Sortino ratios measure return earned per unit of risk (higher is better). And the maximum drawdown — the deepest peak-to-trough fall — is the number that decides whether you can actually stay invested.

Over this particular window the diversification did not pay off: No-Brainer took on nearly as much risk as the S&P 500 for a lower return (Sharpe 0.69 vs 0.72). Its case rests on protecting against risks this stretch simply didn't deliver — a lost decade for US stocks, or an inflation shock.

Figures are computed from monthly adjusted closing prices over May 1996–Jul 2026. Drawdowns are measured at month-end and so understate intra-month extremes.

Methodology

The two instruments

SPY — SPDR S&P 500 ETF: The 500 largest US companies — the standard 'US stocks' holding.
VB — Vanguard Small-Cap ETF: Smaller US companies — higher potential return with bigger swings.
VEA — Vanguard FTSE Developed Markets ETF: Stocks of developed countries outside the US (Europe, Japan, and more).
BND — Vanguard Total Bond Market ETF: A broad basket of investment-grade US bonds — the main stabilizer.

Backtest parameters

Allocation: 25% SPY / 25% VB / 25% VEA / 25% BND
Benchmark: S&P 500 (SPY)
Data: Monthly adjusted closing prices (dividends reinvested)
Period: May 1996 – Jul 2026 (history before an ETF's inception is extended with its older index/mutual-fund equivalent)
Rebalance: Yearly, at month-end
Transaction costs: None modelled

Advantages

Balanced across size and geography: Equal stakes in large-cap, small-cap, and international stocks spread risk across the parts of the market that take turns leading.
Simple enough to actually follow: Four equal slices and a yearly rebalance make it nearly impossible to get wrong — and sticking with a plan is what produces returns.

Disadvantages and risks

Still 75% stocks: With three of four slices in stocks, it takes deep drawdowns in bear markets; the single bond slice only partly cushions them.
Small-cap and international drag: Both trailed US large-caps for much of the past 15 years, so this diversified mix underperformed a plain S&P 500 fund over that period.

Try it yourself

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Frequently asked questions

What is the No-Brainer portfolio?: William Bernstein's equal four-way split — 25% each in the S&P 500, US small-caps, international stocks, and bonds — rebalanced yearly.
Is the No-Brainer portfolio good?: It is a solid, diversified, easy-to-run portfolio well suited to long-term investors. Its main risk is the 75% stock weight, which means large drawdowns in crashes.
Why include small-cap and international stocks?: They behave differently from US large-caps and have historically added return, so mixing them in reduces reliance on any single slice of the market.

References

Educational analysis of historical data, not investment advice. Past performance does not guarantee future results. Backtested results are hypothetical and computed from the MarketHeist portfolio engine on the parameters above.