Misleading Performance Claims
The legal but slanted ways investment performance gets presented, from cherry-picked periods and hypothetical back-tests to returns before fees and survivorship bias, and how to read past them.
The short version
Performance can be presented in many ways, and past results don't predict future ones. Common distortions include cherry-picking the best periods, showing hypothetical back-tested results instead of real ones, quoting returns before fees, choosing a flattering benchmark, and survivorship bias, where failures quietly disappear from the record. Advertising rules for investment advisers require net-of-fee results alongside gross ones and standard 1-, 5-, and 10-year periods. Ask for actual results, after fees, over full market cycles, compared with a fair benchmark.
By the end of this lesson, you'll be able to
- Recognize cherry-picking, hypothetical back-tests, gross-of-fee returns, and unfair benchmarks
- Explain survivorship bias and why luck can look like skill
- Ask the questions that put a performance claim in context
Why this matters
Performance numbers are the most persuasive part of any investment pitch, and the easiest to slant without saying anything false. The SEC's investor bulletin on performance claims stresses that performance can be presented in many different ways and that past performance doesn't necessarily predict future results.1 Knowing the common distortions lets you read any claim on fair terms.
Five common distortions
- Cherry-picking. Showing only periods of good returns, or only the profitable investments. The SEC suggests questioning any presentation that doesn't cover reasonable periods with different market conditions, including both up and down markets.1
- Back-tests. Applying a strategy to past market data to show how it would have done. It's hypothetical, not actual performance, so ask for the real track record.1
- Returns before fees. Fees reduce returns, so ask what was left out of the calculation.1
- The wrong benchmark. Comparing a strategy with an index from a different part of the market, or one that doesn't reflect fees, can flatter it.1
- Convenient start dates. "Up 80% since March" sounds great if March was the bottom of a crash. A fall of 50% followed by a rise of 80% still leaves you 10% below where you started, because 0.5 × 1.8 = 0.9.
What the rules require of advisers
Registered investment advisers face specific advertising rules. An adviser that shows performance before fees must also show it after fees, with at least equal prominence and over the same period. Ads that show a portfolio's results, other than a private fund's, generally must include 1-, 5-, and 10-year periods. The rule treats back-tested results, model portfolios, and targeted or projected returns as hypothetical performance.2 Social media accounts, newsletters, and course sellers often aren't registered advisers, so these standards may not apply to them at all.
The rest of this lesson is for members
Still to come in this lesson: Survivorship bias, Luck can look like skill, the key takeaways, and 2 quiz questions with explanations.
Membership opens every lesson in the curriculum, the capstone projects, the interactive tools, and the members-only channels in the Hyperion Entities Discord. The first lesson of every module stays free.
Go deeper
- Arithmetic and Geometric AveragesMath and Statistics for Investors (depth track)
- Reading Charts HonestlyMath and Statistics for Investors (depth track)
- Index FundsPart 2: What You Can Own
Notes and sources
- Investor.gov, U.S. Securities and Exchange Commission. Investor Bulletin: Performance Claims (September 15, 2022). Checked 2026-10-01. Back to text
- Legal Information Institute, Cornell Law School. 17 CFR 275.206(4)-1: Investment adviser marketing. Checked 2026-10-01. Back to text
- S&P Dow Jones Indices. SPIVA U.S. Mid-Year 2026 (September 17, 2026). Checked 2026-10-01.