How Much Do Your ETFs and Mutual Funds Actually Overlap?

ETF overlap is what happens when two or more funds you hold own the same underlying stocks. If you buy several funds expecting to spread your money across different companies, but those funds hold largely the same names, the money sits in fewer companies than the fund count suggests — and each fund charges its own expense ratio on that same basket. The overlap percentage puts a number on how much of that is happening. What it means for any particular portfolio is for the holder to judge.

For every stock two funds share, the engine takes the lower of the two portfolio weights, then adds those minimums up. That is the standard weighted-overlap measure: it answers “how much of these two portfolios is literally the same money in the same stocks?”

• Two S&P 500 funds land in the 90s — nearly the same portfolio.
• An S&P 500 fund against a total-market fund lands in the 80s–90s.
• An S&P 500 fund against an international fund lands near zero.

Holdings are matched on regulatory security identifiers and resolved to tickers, so share classes and name variants still line up.

Three things, plus a posture:

• ETFs and mutual funds together: most free checkers are ETF-only. Here a Fidelity index fund and a SPDR ETF sit in the same universe and compare directly.
• The SEC’s catalogue, not a shortlist: the universe is built from the SEC’s own list of registered US funds rather than a hand-picked set of popular tickers, so a small Fidelity fund is as comparable here as SPY.
• A minimum-overlap finder: a ranking of the whole universe by how little each fund overlaps one you hold — no mainstream free US tool offers this.

And the posture: no accounts, no tracking, nothing to upgrade to. An independent data utility — it sells nothing.

You name one fund you already hold, and every fund in the universe — ETFs and mutual funds — is ranked by how little its portfolio overlaps yours, weighted and identifier-matched on the same engine as Compare. It ranks on that one dimension only, reading no returns, no ratings and no fees, so the fund at the top of the list is the least-overlapping one rather than the best one. Funds with fewer than ten disclosed holdings are left out, because a handful of positions cannot be compared fairly against a full portfolio; how many were left out is shown with the results, along with how many were ranked. What to do with that information is your decision.

How much the funds inside one portfolio hold the same stocks as each other. You build a portfolio of up to ten funds with the allocations you actually use — up to five portfolios, side by side — and each gets a single figure: the allocation-weighted average of the overlap between every pair of funds in it, computed on the same engine as Compare. A lower number means the funds repeat one another less. It reads composition only, with no returns, ratings or fees involved, so it cannot say which portfolio performed better and neither is ranked above the other. Funds with no equity portfolio to compare — money-market, bond and feeder funds, and bullion or coin trusts — are named rather than quietly dropped, and the score is measured across the matched funds only.

Two public sources:

• SEC EDGAR Form N-PORT — the portfolio disclosure every US registered fund must file. It covers both ETFs and mutual funds and is the universal baseline.
• Fund sponsors’ published daily holdings files — for ETFs whose sponsors publish them, these refresh the weights daily.

Every result shows the as-of date of the data behind it.

It varies by fund, and the as-of date ships with every result rather than being hidden. ETFs refreshed from sponsor daily files carry prior-close weights. Funds sourced from SEC filings carry the filing period’s date — SEC rules make those filings public roughly two months after the period ends. Overlap percentages move slowly, because portfolio weights drift gradually, so an eight-week-old snapshot still describes a fund’s shape well.

The universe is built from the SEC’s own catalogue of every registered US fund — all issuers, ETFs and mutual funds alike — so any fund that files portfolio disclosures is coverable, including QQQ. The structural exceptions are single-asset trusts (gold, silver, bitcoin vehicles such as GLD or IBIT), which hold bullion or coin rather than a portfolio of securities, so there is nothing to overlap. If a fund you hold is missing, tell us via the contact page — if it files with the SEC, it can be added.

No. ETF & Fund Analysis is an independent data utility. Every number on it is computed from public regulatory filings and fund disclosures — what funds report they hold — and describes composition, never performance. The severity badges and rankings label what those numbers show. None of it is a recommendation to buy, sell or hold any security, and the site is not an investment adviser. What to do with the numbers is your decision.