Portfolio benchmark: pick the right benchmark, compare portfolio performance, and build a blended benchmark that fits.
The S&P 500 is the wrong yardstick for almost every real portfolio. Build the blend that matches what you actually hold, then measure against that.
Educational only · Never places a trade
In short
A portfolio benchmark is the index you measure your holdings against, and choosing one that matches what you own is the entire job. Most investors default to the S&P 500, which fits only a portfolio of US large-cap stocks. If you hold mid caps, small caps, international shares, REITs or bonds, that index will flatter or punish you for reasons that have nothing to do with your decisions. The professional answer is a blended benchmark: weight several indexes to match your allocation and compare against the blend. That is exactly what S&P Dow Jones Indices does in its own SPIVA scorecards, where large-cap funds are scored against the S&P 500, mid caps against the S&P MidCap 400 and small caps against the S&P SmallCap 600, never all against one index.
Last updated July 2026
Portfolio benchmark comparison
Which benchmark actually fits what you hold
The pairings below follow the same discipline S&P Dow Jones Indices applies when it scores funds: each category is judged against the index built for it. Find the row that describes your holdings.
| What you hold | Benchmark that fits | Why |
|---|---|---|
| A portfolio of US large-cap stocks | S&P 500 | The default choice, and the only portfolio it genuinely fits. If your holdings are large US companies, this is the right yardstick. |
| US mid-cap holdings | S&P MidCap 400 | Mid caps move on a different cycle. Measuring them against the S&P 500 tells you about size exposure, not about your picks. |
| US small-cap holdings | S&P SmallCap 600 | Small caps can trail large caps for years at a stretch. Against the wrong index you will fire a strategy that was working. |
| A total US market portfolio | S&P Composite 1500 | Covers large, mid and small in one index, so it fits a portfolio that deliberately reaches across the whole US market. |
| A value-tilted portfolio | S&P 500 Value or S&P SmallCap 600 Value | Style matters as much as size. A value portfolio judged against a growth-heavy index is being scored on a factor bet it never made. |
| International developed holdings | S&P World Ex-U.S. | Currency and country weights dominate here. A US index cannot separate your stock selection from the dollar. |
| A global portfolio | S&P World Index | The honest benchmark when you deliberately own the world rather than one country. |
| US real estate holdings | S&P United States REIT | REITs trade on rates and cap rates. They belong against a REIT index, not against the broad market. |
| A crypto basket | BTC, or a weighted blend | Bitcoin is the reference asset most crypto baskets are implicitly measured against. See the crypto index page for why weighting decides the answer. |
| A mixed stock and bond portfolio | A blended benchmark | No single index fits. Weight the component indexes to match your allocation, which is what the rest of this page is about. |
One rule covers most mistakes: the benchmark should hold roughly the same kind of thing your portfolio holds. If it does not, the gap you are reading is an asset allocation difference wearing the costume of a performance result. A portfolio that is 30% bonds will trail the S&P 500 in a strong equity year no matter how well the stock sleeve was chosen, and it will beat the S&P 500 in a bad one. Neither outcome tells you anything about your selection.
Use total return versions of every index, not price return. The S&P 500 price index leaves out dividends, so measuring against it quietly hands your portfolio a couple of percentage points a year that it did not earn. If you specifically want the S&P 500 comparison, the compare your portfolio to the S&P 500 page walks through that one case, and benchmark comparison charting covers plotting the two lines together.
How hard is a benchmark to beat
What the SPIVA data says about beating your benchmark
Percentage of actively managed US funds that underperformed their matched benchmark index. Source: SPIVA U.S. Scorecard Mid-Year 2025, S&P Dow Jones Indices LLC and CRSP, data as of June 30, 2025.
| Fund category | Comparison index | 10 years | 15 years | 20 years |
|---|---|---|---|---|
| All Large-Cap Funds | S&P 500 | 85.98% | 88.29% | 91.03% |
| All Mid-Cap Funds | S&P MidCap 400 | 76.84% | 83.72% | 88.81% |
| All Small-Cap Funds | S&P SmallCap 600 | 78.42% | 85.41% | 87.81% |
| All Multi-Cap Funds | S&P Composite 1500 | 89.11% | 90.85% | 93.17% |
| Large-Cap Value Funds | S&P 500 Value | 89.40% | 91.96% | 86.22% |
| Small-Cap Value Funds | S&P SmallCap 600 Value | 72.80% | 87.50% | 88.89% |
| Real Estate Funds | S&P United States REIT | 81.72% | 87.00% | 90.36% |
| All Domestic Funds | S&P Composite 1500 | 90.31% | 92.52% | 93.81% |
Two things fall out of that table. The first is the obvious one: over 15 years, 88.29% of large-cap funds failed to beat the S&P 500, and 92.52% of all domestic funds failed to beat the S&P Composite 1500. Professionals with research teams lose to the index most of the time, which is the strongest argument there is for holding a broad index and for being honest with yourself about the comparison.
The second is easier to miss and matters more here. Every row uses a different index. S&P did not score mid-cap funds against the S&P 500, because doing that would have measured the size cycle rather than the managers. Over the ten years to June 2025, 76.84% of mid-cap funds trailed the S&P MidCap 400. Score those same funds against the S&P 500 over a decade when large caps led and the number would look far worse, and it would be telling you about market cap, not about skill. That is the mistake most individual investors make with their own portfolios every quarter.
Note that these are underperformance rates measured to a single date. Underperformance rates swing hard year to year and settle only at longer horizons, so a benchmark gap measured over one quarter carries almost no information. Past performance is no guarantee of future results.
Portfolio benchmark return
How to build and calculate a blended benchmark
A blended benchmark is a weighted average of the indexes that match your sleeves. The calculation is simple arithmetic, and doing it once usually changes how a year reads.
The calculation
Multiply each component index return by its target weight, then add them together. Take a portfolio held at 60% US equities and 40% bonds. If the equity index returned 12% over the period and the bond index returned 3%, the benchmark return is:
(0.60 x 12%) + (0.40 x 3%)
= 7.2% + 1.2%
= 8.4%
Illustrative figures, not market data. Always use total return index versions so dividends and coupons are counted.
Why it changes the verdict
Suppose that portfolio returned 7.0%. Measured against the S&P 500 at 12%, it looks like a 5.0 point failure and plenty of people would tear the strategy up on that basis. Measured against its actual benchmark of 8.4%, the gap is 1.4 points, which is a normal shortfall worth investigating in fees, cash drag or selection.
Same portfolio, same year, two completely different conclusions. The only variable is whether the benchmark matched the allocation. This is why benchmark selection is not a technicality.
One detail catches people out. A blended benchmark has to be rebalanced back to its target weights on a stated schedule, usually quarterly or annually. If you never rebalance it, the equity sleeve grows through a bull market until a benchmark you set up as 60/40 is behaving like 75/25, and it will start beating your portfolio simply for being more aggressive. Decide the schedule when you build the blend and write it down. The mechanics are covered in portfolio rebalancing, and the weighting choices themselves in index construction.
How it works
Build your benchmark in four steps
Write down what you actually hold
Split the portfolio into sleeves by asset class, size and region, with a percentage against each. Most people discover here that their real allocation is not the one they think they have.
Pick an index per sleeve
Use the table above. Large caps to the S&P 500, mid caps to the S&P MidCap 400, international to a world ex-US index, and so on. Total return versions only.
Blend to your weights
Build the weighted combination as a single index in Indexes, so the benchmark becomes one line you can chart instead of a spreadsheet you rebuild every quarter.
Backtest it, then track the gap
Run your portfolio and the blend over the same dates, read the drawdowns alongside the returns, and keep tracking the gap so the comparison stays live rather than annual.
Indexes is educational and informational software for designing, testing and tracking an index. It never places trades, connects to a brokerage or holds assets, and every backtest is hypothetical historical performance that does not predict future returns.
Who benchmarks properly
Who this is actually for
Self-directed investors with a mixed portfolio
If you hold bonds, international stocks or small caps alongside US large caps, no published index fits you. The blend is the only comparison that will tell you the truth about your own decisions.
Anyone deciding whether to fire a strategy
Abandoning an approach after a bad stretch against the wrong benchmark is one of the most expensive mistakes available. Get the yardstick right before you make the call.
Advisors reporting to clients
A stated, rebalanced blended benchmark set in advance is what makes a performance conversation defensible. Choosing the benchmark after the fact is how those conversations go wrong.
People testing a thesis basket
A theme basket needs a benchmark chosen before the test, not after. See thematic investing for how that plays out in practice.
Crypto basket holders
Most crypto baskets are measured against Bitcoin whether the holder admits it or not, because cap weighting makes them mostly Bitcoin. The crypto index page covers the construction side.
Equal weight and factor tilters
If you deliberately hold an equal weight index, comparing it to the cap weighted S&P 500 measures your tilt, which is the point, as long as you know that is what you are reading.
Questions
Portfolio benchmarks, answered
What is a portfolio benchmark?
A portfolio benchmark is the index or blend of indexes you measure your portfolio against, so you can tell whether a result came from your decisions or from the market. It sets the standard of comparison. Without one, a 9% year is just a number, because you cannot say whether the market handed you 12% or 4%.
What is the purpose of a benchmark in portfolio management?
A benchmark separates skill from market movement. It answers the only question that matters about performance: could you have had this result for nothing by owning the index instead? It also sets expectations for risk, since a good benchmark carries roughly the same asset mix and volatility as the portfolio it judges.
Is the S&P 500 a good benchmark for my portfolio?
Only if your portfolio is essentially US large-cap stocks. The S&P 500 holds 500 large US companies and nothing else, so it is the wrong reference for a portfolio holding bonds, small caps, international stocks or real estate. Against it, a diversified portfolio will look like it is losing in almost every year that US large caps lead.
What is a good benchmark for a 60/40 portfolio?
A blended benchmark of 60% equity index and 40% bond index, rebalanced to those weights on a set schedule. For a US-only version that is 60% S&P 500 and 40% a broad US bond index. The blend has to be rebalanced, otherwise the equity sleeve drifts upward and the benchmark quietly becomes more aggressive than your portfolio.
What is a blended benchmark?
A blended benchmark is a custom index built by weighting several benchmarks to match a portfolio allocation. A portfolio that is 50% US large cap, 20% international and 30% bonds gets a benchmark weighted the same way. It exists because most real portfolios do not match any single published index.
How do you calculate a portfolio benchmark return?
Multiply each component index return by its target weight, then add the results. A benchmark of 60% equities returning 12% and 40% bonds returning 3% returns 0.60 times 12 plus 0.40 times 3, which is 8.4%. Use total return versions of each index so dividends and coupons are included, otherwise the benchmark is understated.
How do I compare my portfolio to an index?
Model your holdings and their weights as a single index, then chart both over the same start and end dates using total return figures. Comparing a portfolio ticker by ticker against an index tells you very little. The comparison only means something when your holdings are combined into one weighted line.
How often should I compare my portfolio to its benchmark?
Review quarterly, judge over full market cycles. Quarterly checks catch drift and let you see whether the gap has an explanation. Drawing conclusions about a strategy needs several years, because SPIVA data shows underperformance rates swinging widely from one year to the next before settling at longer horizons.
Measure against something that fits
Build the blended benchmark your portfolio deserves, backtest the comparison over real history, and track the gap from there. No account, no minimum, no trades. Educational and informational only.