The five-factor check, and which factor actually binds#
There’s a standard checklist for evaluating an ETF, and it’s a good one. Risk and volatility. Track record. What it holds. Costs. Sector allocation.
Four of those measure the fund. One measures whether you can hold it. Guess which one decides your return.
Take Vanguard’s VFV, the S&P 500 ETF listed on the TSX, as a worked example. Track record: 1-year +20.73%, 3-year annualised +24.84%, 10-year +15.39%. A thousand dollars at inception grew to $6,561 by April 2025 — a 16.25% compound annual return. Beautiful numbers.
Now the other one. Worst three-month return: −13.68%. Your $1,000 becomes $863 in a quarter.
Which of those figures will determine whether you still own this fund in 2040?
Why the worst quarter is the honest question#
The return figures describe a fund that existed during a specific and unusually good stretch of market history. The worst-quarter figure describes an experience you will personally have to sit through.
The test is simple and uncomfortable: picture the balance, not the percentage. If you invest $40,000 and the screen says $34,500 next quarter, what do you do? If the honest answer involves selling, the fund is too risky for you regardless of its Sharpe ratio, its expense ratio, or how confidently you can explain compound growth at a dinner party.
And VFV’s −13.68% is a mild version of the question. It’s the worst quarter in that fund’s short history, not the worst quarter the S&P 500 has produced. The index fell 57% from its October 2007 peak to the March 2009 trough. A fund launched after 2009 has simply never been asked the real question.
The supporting metrics, and what they’re for#
The rest of the risk section is useful once you understand each metric answers a different question.
Standard deviation (VFV: 11.76%) measures how much annual returns vary. It’s the volatility number, and for a long-term holder it’s the least important of the three.
Beta (VFV: 1.00) measures sensitivity to the benchmark. Exactly 1.00 means it moves one-for-one with the S&P 500 — which is what you want from an index fund and would be alarming from anything claiming to be defensive.
R-squared (VFV: 1.00) confirms tracking fidelity. This is the one that tells you the fund is doing its job. A passive fund with a low R-squared against its stated benchmark is not tracking the thing it says it tracks.
Beta and R-squared together are a fidelity check. Standard deviation and worst-quarter are the risk check. Don’t let the first pair reassure you about the second.
NAV, market price, and the spread#
One mechanical detail worth ninety seconds. An ETF has two prices. NAV — net asset value — is total holdings divided by units outstanding, the true per-unit worth, calculated after the close. Market price is what supply and demand set during the day.
They converge by end of day when the fund is liquid. The tell is the bid-ask spread: VFV’s is 0.02%, which signals plenty of liquidity and fair pricing. A wide spread on a thinly traded ETF is a real cost, charged on both entry and exit, and it doesn’t appear in the expense ratio.
Check the spread on anything niche. On mainstream trackers it’s a rounding error.
Costs: the small number that isn’t small#
VFV’s MER is 0.09% — 90 cents a year per $1,000. Actively managed funds often run 2% or more.
The way to feel that gap is over time rather than per year. A 0.41% difference between two otherwise similar ETFs compounds into thousands of dollars of foregone growth across 30 years. The fee is deducted whether the fund rises or falls, which is exactly what makes it the most reliable number in the document.
Also check the trading expense ratio (VFV: 0.00%) and watch for expense waivers — a provider can waive fees temporarily, and the headline MER isn’t necessarily the permanent one.
What you’re actually holding#
VFV tracks the S&P 500 and holds 505 companies. As of April 2025 the top five were Apple 6.8%, Microsoft 6.2%, Nvidia 5.6%, Amazon 3.7%, Alphabet 3.6% — with the top 10 at 35.6% of the fund. Those weights move: Nvidia had grown to 8.0% by September.
Sector allocation tells the same story more clearly. Information Technology was 30.4%, rising to 34.8% by September, with Financials 14.4% and Healthcare 10.8% behind it. Market-wide the concentration has kept climbing — Information Technology sits near 38% of the S&P 500 as of mid-2026.
Which loops directly back to the worst-quarter question. A fund that’s more than a third technology by weight will produce a worse worst-quarter in the next tech correction than it did in the last one. The −13.68% is a floor built on a different index composition than the one you’re buying today.
Summary — and what to do about it#
Fund selection is mostly solved. Whether you hold on is not.
- Find the worst 3-month return first. Convert it to dollars on your actual investment amount. Sit with the number.
- If that figure would make you sell, choose something tamer. A worse fund you keep beats a better fund you abandon.
- Use beta and R-squared as a fidelity check. Near 1.00 against the stated benchmark means the fund does what it claims.
- Check the bid-ask spread on anything niche. It’s a real cost paid twice and it’s not in the MER.
- Compare MER as a 30-year figure, not an annual one. 0.41% sounds trivial and isn’t.
- Add the sector table to your existing holdings. Your total tech exposure is the number that matters, not any single fund’s.
- Download both documents. ETF Facts and the Fund Facts sheet are legally required to be free and public. Read them before you buy, not after the drop.
The average return tells you about the fund. The worst quarter tells you about you. Only one of those is under your control.
Sources & further reading#
- Federal Reserve History, “The Great Recession” — the 57% peak-to-trough decline in the S&P 500.
- AlphaEx Capital, S&P 500 sector breakdown 2026 — Information Technology near 38% of index weight.
- Pensions & Investments, S&P 500 index concentration — top 10 holdings approaching 40% of the index.
