Stocks, Bonds, Bills, and Inflation was a long-running U.S. capital-market data series and annual yearbook used to compare historical asset-class returns.
Stocks, Bonds, Bills, and Inflation (SBBI) refers to a long-running U.S. capital-market dataset and publication series associated with Roger Ibbotson and Rex Sinquefield. It compiled historical returns for major stock and fixed-income categories alongside inflation, with core series extending back to 1926. The annual SBBI Yearbook is now discontinued, so an analyst using it must identify the edition, its ending date, and any separate source used to update the history.
SBBI is historical evidence, not a forecast and not an investable portfolio. Its value comes from consistent long-horizon comparisons and detailed series definitions.
The full yearbooks included returns, index values, and statistical analysis for several U.S. capital-market series. Coverage varied by edition, but commonly included:
| Historical series | Broad exposure represented | Question to verify |
|---|---|---|
| Large-company stocks | U.S. large-cap equity total returns | Which stock index and reinvestment convention? |
| Small-company stocks | A small-cap or micro-cap equity series | Did the proxy or construction change over time? |
| Long-term corporate bonds | Long-maturity corporate fixed income | Which credit-quality and maturity rules? |
| Long-term government bonds | Long-duration U.S. government securities | Was a constant-maturity or one-bond portfolio used? |
| Intermediate government bonds | Medium-maturity U.S. government securities | How was the replacement security selected? |
| Treasury bills | Short-term U.S. government bills | Which maturity and reinvestment rule? |
| Inflation | U.S. consumer-price change | Which CPI series and timing convention? |
The labels are convenient summaries. They do not make unlike asset classes equally liquid, equally risky, or directly investable under the same costs and taxes.
Ibbotson and Sinquefield’s 1976 research assembled year-by-year U.S. returns beginning in 1926. Ibbotson Associates later developed the material into the familiar SBBI publication and data products.
The publication lineage then changed:
| Period | Publisher or steward | Practical implication |
|---|---|---|
| Before 2007 | Ibbotson Associates | Early editions and series definitions must be read in their historical context |
| 2007-2015 | Morningstar | Editions may use Morningstar branding and licensed SBBI data |
| 2016-2023 | Duff & Phelps, later Kroll | The yearbook remained a historical U.S. capital-market reference |
| After 2023 | No new annual SBBI Yearbook | Current analysis requires clearly identified replacement data |
The absence of a new yearbook does not invalidate the historical observations. It does mean that phrases such as “the latest SBBI return” are no longer self-explanatory.
SBBI comparisons often distinguish nominal return from growth in purchasing power. The exact real return is:
where (\pi) is the inflation rate over the same period.
Suppose a stock benchmark earns a 10% nominal total return while inflation is 4%:
Simply subtracting 4% from 10% gives 6%, which is a close approximation at modest rates but not the exact compounded result. Taxes, investment fees, and trading costs would reduce an investor’s realized outcome further and are separate from the benchmark calculation.
Historical return discussions can produce different “average” returns from the same observations.
| Average | Calculation | Best answers |
|---|---|---|
| Arithmetic mean | Add periodic returns and divide by the number of periods | What was the average one-period observation? |
| Geometric mean | Compound the returns and solve for the constant growth rate | What constant annual rate links beginning and ending wealth? |
If an investment rises 50% and then falls 50%, its arithmetic average return is 0%:
But $100 becomes $150 and then $75. The two-period geometric return is:
Quoting “the historical average” without naming the averaging method can therefore be materially misleading.
The history can show that higher long-run returns came with substantial year-to-year variation and severe drawdowns. It provides context for risk, but it does not prove that the same ranking will hold over a particular future horizon.
Comparing nominal asset returns with inflation shows whether a benchmark increased real purchasing power. The inflation series still may not match an individual household’s spending pattern.
Analysts have used SBBI data to estimate historical differences between stocks and government securities. A historical premium is sensitive to the start date, end date, averaging method, selected risk-free proxy, and whether the analysis uses income or total returns. It is not automatically a forward-looking expected return.
The data can illustrate compounding, volatility, recovery periods, and the difference between nominal and real wealth. Those lessons remain useful even when the publication itself is no longer updated.
This page is educational and does not provide personalized investment, valuation, tax, or retirement advice.