ETF Overlap Map: You Might Own the Same 10 Stocks Everywhere

Key Takeaways

• Check each ETF's top 10 holdings before you assume you are diversified.
• If the same few stocks appear in many ETFs you own, your true diversification may be overstated.
• Create a simple overlap map by listing top holdings and counting repeats to measure concentration.
• Use ETF provider pages and free tools to compare holdings quickly, or build a spreadsheet for ongoing monitoring.
• A practical rule: if three or more of your ETFs share five or more of the same top 10 holdings, review your allocation.

Introduction

An ETF overlap map is a quick way to see whether the ETFs you own are really diversifying your portfolio or just repackaging the same handful of stocks. In plain language, it helps you find hidden concentration across funds that look different on the surface.

Why does this matter to you? Because owning multiple ETFs that all hold the same top stocks can leave you exposed to the same risks you thought you had reduced. Want to avoid that surprise? You will learn how to check ETF top holdings, how to build a simple overlap map, and what actions to take if you find too much repetition.

This article covers step by step how to compare holdings, practical examples using well known tickers, simple rules of thumb to follow, common mistakes to avoid, and answers to the most likely questions you will have. Ready to see what you might really own?

Why ETF Overlap Happens

ETFs track indexes or themes and they build portfolios that follow those rules. When large companies dominate multiple indexes, they also dominate the ETFs tied to those indexes. That creates overlap across funds that otherwise look different.

For example, many broad market ETFs and technology focused ETFs both hold $AAPL, $MSFT, and $NVDA near the top. That means you can own a total market ETF, a growth ETF, and a tech ETF and still be heavily exposed to the same handful of mega-cap stocks.

How market cap weighting increases overlap

Most large index ETFs weight holdings by market capitalization. When a few companies have very large market values, they grab large slices of many market cap weighted funds. That naturally creates repetition in ETF top holdings.

So even if you buy different single ETFs, market cap weighting can make your overall exposure less diverse than you expect.

How to Check Top Holdings Step by Step

Checking ETF overlap is straightforward and you can do it in 10 to 30 minutes. Here is a simple process you can follow now.

1. List the ETFs you own or plan to buy. Write down the ticker symbols so you can look them up quickly.
2. Visit each ETF provider page or a trusted data site and find the fund's top 10 holdings. Most providers list holdings and weights on the fund facts page.
3. Record each top holding and its weight in a spreadsheet. Create columns for ETF ticker, holding ticker, and weight percent.
4. Count repeats across ETFs. For each stock, count how many ETFs include it in their top 10.
5. Calculate simple concentration measures. Add the weights of all repeated stocks across your combined allocation to see how much of your total portfolio sits in those names.

Tools you can use

Use ETF provider pages like iShares, Vanguard, or State Street to get official lists. Free sites that compare holdings include Morningstar, ETFdb, and JustETF. You can also use broker tools that show overlapping holdings automatically.

If you prefer manual work you can copy the top 10 into a spreadsheet and use COUNTIF to tally repeats. Either approach works depending on how often you want to check.

Practical Example: Three ETFs, One Cluster of Stocks

Here is a concrete example to make the method tangible. Imagine you have three ETFs in a small portfolio.

1. $SPY, an S&P 500 ETF
2. $QQQ, a Nasdaq 100 ETF
3. $VGT, a U.S. technology ETF

Step one is to list each fund's top 10 holdings and their weights. For simplicity in this example we will use rounded illustrative weights. Your numbers will differ slightly day to day.

• $SPY top holdings might include $AAPL 7.0, $MSFT 6.5, $AMZN 3.5, $NVDA 3.0, $GOOGL 3.0
• $QQQ top holdings might include $AAPL 12.0, $MSFT 11.0, $NVDA 8.0, $AMZN 4.5, $TSLA 4.0
• $VGT top holdings might include $AAPL 12.0, $MSFT 11.0, $NVDA 9.0, $ADBE 4.0, $CRM 3.5

Now build a simple overlap map by listing each unique stock and counting how many of your three ETFs include it in their top 10.

• $AAPL appears in all three ETFs, count 3
• $MSFT appears in all three ETFs, count 3
• $NVDA appears in all three ETFs, count 3
• $AMZN appears in $SPY and $QQQ, count 2
• $GOOGL appears only in $SPY top 10, count 1

Next approximate the combined weight exposure for the top repeated names. If you hold equal dollar amounts in the three ETFs you can average the weights or calculate the proportion of your portfolio in each ETF and then multiply by the stock weights. In this example the three names repeated across all ETFs represent a meaningful slice of your total allocation.

What does that tell you? Even though you own three different ETFs, a handful of mega-cap stocks dominate your exposure. That means your portfolio's performance may closely track those companies, reducing the benefit of diversification.

Simple Rules and Metrics to Use

Beginners need simple, repeatable rules. Here are practical thresholds and measures you can use the next time you review your holdings.

• Top 10 repeat rule, simple: if five or more of the same stocks appear in the top 10 lists of three or more ETFs you own, dig deeper.
• Top 10 weight rule: if the sum of the top 10 weights across your combined ETFs is more than 40 percent of your total allocation, your portfolio is concentrated.
• Count rule: list unique top holdings and count how many ETFs include each. Greater counts equal more overlap and more hidden concentration.

Why simple rules work for beginners

Complex math can be helpful but also confusing. These simple tests give you a fast signal so you can decide whether to spend more time analyzing your portfolio. You can check overlap quarterly or when you add a new ETF.

How to Reduce Unintended Overlap

If your overlap map shows repetition you have choices depending on your goals and timeline. Here are practical steps you can take.

• Rebalance your allocations so no single ETF or group of repeated holdings dominates the portfolio.
• Choose ETFs with different weighting methods, such as equal weight or factor based funds, to reduce concentration in mega-cap stocks.
• Add complementary asset classes like bonds, international stocks, or small cap funds that have different top holdings.
• Use targeted single stock exposure only if you want to take a deliberate bet on a company. Otherwise favor broad, non overlapping funds.

Remember, you do not have to eliminate overlap entirely. Many investors accept some overlap because large companies are a legitimate part of diversified portfolios. The key is to know what you own and make conscious choices.

Common Mistakes to Avoid

• Assuming different ETFs equal diversification, without checking holdings. How the fund is constructed matters more than its name.
• Relying only on the ETF category or label. Two ETFs labeled "growth" can still have very different top holdings and similar concentrations.
• Ignoring weights and focusing only on whether a stock is present. A stock at 0.1 percent is less important than one at 10 percent.
• Failing to update overlap checks. ETF holdings change over time as indexes rebalance and market caps shift, so check regularly.
• Chasing diversification by adding more ETFs without reducing existing overlap. More funds can increase complexity without reducing risk.

FAQ

Q: How often should I check ETF overlap?

A: Check at least once every quarter and any time you add a new ETF. Quarterly checks align with many index rebalances and keep you aware of shifting weights.

Q: Are overlapping holdings always bad?

A: No. Overlap is not automatically bad because large, high quality companies often deserve significant portfolio weights. The issue is hidden concentration that you did not intend.

Q: Can I use my broker's tools to find overlap?

A: Yes. Many brokers show overlapping holdings across your entire account. Those tools are convenient, but you should confirm with the ETF provider's official holdings page when making decisions.

Q: What if I want exposure to a popular stock across multiple ETFs?

A: You can accept that exposure, but do it intentionally. Know the total percentage of your portfolio tied to that stock and consider reducing exposure elsewhere if the combined allocation is larger than you want.

Bottom Line

Creating an ETF overlap map is a simple, high value step that helps you see whether your ETFs actually give you diverse exposure or just amplify the same few names. You can do a basic overlap check in 10 to 30 minutes using provider data or broker tools.

Start by listing top 10 holdings for each ETF, count repeats, and estimate combined weights. If repeated names dominate your portfolio, consider rebalancing, adding different weighting styles, or introducing other asset classes. At the end of the day, the goal is for your investments to reflect your intentions, not a surprise concentration you did not plan for.