What Is ETF Overlap? How to Check and Reduce It

Owning several exchange-traded funds may make a portfolio look diversified. But if those ETFs hold many of the same stocks, your investments may be less diversified than they appear.

This is known as ETF overlap.

ETF overlap occurs when two or more ETFs own the same securities. A small amount of overlap is normal and is not automatically harmful. However, excessive overlap may concentrate your portfolio in a few companies, sectors, or investment styles without you realizing it.

This guide explains how ETF overlap works, how to measure it, how much may be too much, and what you can do about it.

What Is ETF Overlap?

ETF overlap refers to the shared holdings between two or more exchange-traded funds.

An ETF pools investors’ money and invests it in a portfolio of securities. Each ETF share represents an ownership interest in that underlying portfolio, according to the U.S. Securities and Exchange Commission’s ETF guidance.

Suppose you own:

• A broad U.S. stock market ETF
• An S&P 500 ETF
• A large-cap growth ETF

These funds have different names and may track different indexes. However, all three could hold substantial positions in many of the same large U.S. companies.

As a result, buying all three does not necessarily give you three completely different groups of investments.

A Simple ETF Overlap Example

Imagine two fictional funds:

Fund A

• Alpha Corp: 8%
• Beta Inc: 6%
• Gamma LLC: 4%
• Other investments: 82%

Fund B

• Alpha Corp: 5%
• Beta Inc: 4%
• Delta Ltd: 6%
• Other investments: 85%

The two funds share Alpha Corp and Beta Inc.

A basic weighted-overlap calculation would take the smaller weight for each shared holding:

• Alpha Corp: 5%
• Beta Inc: 4%

That produces approximately 9% weighted overlap between the two funds.

This example is intentionally simple. Real ETFs can contain hundreds or thousands of holdings, and different comparison tools may calculate overlap differently.

Why Does ETF Overlap Happen?

Overlap frequently occurs because stock indexes are not completely independent of one another.

Broad-market and large-cap funds

A total U.S. stock market fund generally contains many of the same major companies found in an S&P 500 or other large-cap fund.

Adding a large-cap fund to a total-market position may therefore increase exposure to companies already held in the portfolio.

Broad-market and sector ETFs

A broad-market ETF may already have significant exposure to technology, financial services, healthcare, or another large sector.

Adding a sector ETF creates an intentional or unintentional additional concentration in that area.

Growth funds and market indexes

Growth ETFs often give their largest weights to prominent growth-oriented companies. Some of those same companies may also occupy the largest positions in broad-market indexes.

Similar funds from different providers

Two ETFs offered by different companies may track the same index or highly similar indexes. Different fund names and ticker symbols do not guarantee meaningful diversification.

Multiple accounts

Overlap can also remain hidden when investments are divided among:

• An employer-sponsored retirement plan
• An individual retirement account
• A taxable brokerage account
• A spouse’s investment accounts

Each account might appear diversified by itself, while the combined household portfolio remains concentrated.

Types of ETF Overlap

Overlap is not limited to the number of stocks two ETFs have in common.

Holdings overlap

This measures how many individual securities appear in both funds.

For example, if two ETFs share 40 stocks, those are overlapping holdings. But this figure alone does not reveal how important those positions are.

Weighted overlap

Weighted overlap accounts for the percentage each shared holding represents within the ETFs.

Two funds might share many securities, but each shared position may be very small. Conversely, they might share only a few companies that make up a substantial percentage of both portfolios.

Weighted overlap generally provides more useful context than a simple count.

Sector overlap

Two ETFs may hold different companies but still be concentrated in the same sector.

For example, separate ETFs could invest in different technology businesses while both depending heavily on the performance of the technology industry.

Style and factor overlap

Funds may also share exposure to similar characteristics, such as:

• Large-cap stocks
• Growth stocks
• Value stocks
• Dividend-paying companies
• Low-volatility stocks
• Momentum strategies

Different holdings do not always mean different investment risks.

Geographic overlap

International and global ETFs may overlap as well. A global fund may already include U.S. stocks, while an international fund could overlap with regional or country-specific ETFs elsewhere in the portfolio.

Is ETF Overlap Bad?

ETF overlap is not automatically bad.

Some overlap is common because major companies appear in numerous indexes. The more important question is whether the overlap supports your investment plan or creates concentration you did not intend.

Overlap may be reasonable when you deliberately want to:

• Increase exposure to a particular sector
• Favor growth or value stocks
• Add more weight to small companies
• Maintain positions with substantial unrealized gains
• Transition gradually from one portfolio structure to another
• Hold similar investments in accounts with different purposes

Overlap becomes more concerning when it results from buying funds without examining their underlying holdings.

How Much ETF Overlap Is Too Much?

There is no universal percentage at which ETF overlap becomes unacceptable.

A fixed threshold can be misleading because the significance of overlap depends on:

• Your financial goals
• Your investment time horizon
• Your risk tolerance
• The size of each ETF position
• The companies and sectors involved
• Your other assets and accounts
• Whether the overlap is intentional

For instance, a high overlap between two small positions may have little effect on the overall portfolio. A lower overlap between two funds that make up most of your investments could be more significant.

Ask these questions instead:

1. Are my largest company positions bigger than I intended?
2. Does one sector dominate the portfolio?
3. Do multiple ETFs serve essentially the same purpose?
4. Would these funds likely decline for the same reasons?
5. Am I paying for several funds without receiving meaningful diversification?
6. Can I explain the role of every ETF I own?

If several funds have nearly identical objectives and holdings, the portfolio may be more complicated than necessary.

How to Check ETF Overlap Manually

You can evaluate overlap without specialized software.

Step 1: List all your ETFs

Include ETFs across all brokerage, retirement, and household accounts. Also record how much money you have invested in each fund.

Portfolio-level overlap depends partly on position size. A duplicated holding inside a small ETF position will affect your portfolio differently from the same duplication inside your largest position.

Step 2: Identify each fund’s role

Write down why you own each ETF. Possible roles include:

• Core U.S. stock exposure
• International diversification
• Bonds
• Small-cap stocks
• A particular sector
• Dividend income
• A tactical investment tilt

If two funds have exactly the same role, examine them more closely.

Step 3: Visit the fund provider’s website

Look for:

• Full holdings
• Top holdings
• Sector allocation
• Geographic allocation
• Index tracked
• Expense ratio
• Prospectus
• Shareholder reports

Registered ETFs provide prospectuses and regular reports. Investor.gov explains that these documents can be obtained through the fund or the SEC’s EDGAR database.

Step 4: Compare the largest holdings

Begin with each ETF’s top 10 or 20 holdings.

Create a simple table showing:

• Company name
• Weight in Fund A
• Weight in Fund B
• Weight in any additional funds

Repeated names with large allocations deserve the most attention.

Step 5: Compare sector allocations

A portfolio can remain concentrated even when the funds do not share identical securities.

Compare exposure to sectors such as:

• Information technology
• Financial services
• Healthcare
• Consumer discretionary
• Industrials
• Energy

Step 6: Calculate portfolio-level exposure

Suppose an ETF represents 40% of your portfolio and a company represents 8% of that ETF.

Your indirect portfolio exposure through that fund is:

40% × 8% = 3.2%

Perform the same calculation for other ETFs holding that company, then add the results.

This provides a more realistic estimate of your total exposure than looking at each ETF separately.

How to Use an ETF Overlap Tool

ETF comparison and overlap tools can make the process faster.

Examples include ETF Research Center’s overlap tool and ETF.com’s fund-comparison resources. A typical tool asks for two ticker symbols and may display:

• Number of shared holdings
• Percentage of holdings in common
• Weighted overlap
• Top overlapping securities
• Sector allocations
• Fund costs

However, tool results should be treated as a starting point—not a final investment decision.

Data may differ because:

• ETF holdings change
• Providers update data at different times
• Tools may use different overlap formulas
• Some funds disclose holdings on different schedules
• Derivatives or cash positions may be classified differently

Confirm important information on the official fund provider’s website.

How to Reduce ETF Overlap

Reducing overlap does not mean eliminating every duplicated holding. The goal is to make the portfolio deliberate, understandable, and aligned with your needs.

Define a core holding

Some investors use one diversified fund as the foundation of the portfolio. Additional ETFs are then added only when they provide exposure the core fund does not adequately cover.

Before selecting multiple funds, consider how many ETFs you may actually need to meet your diversification goals.

Remove unnecessary duplicates

If two ETFs track the same index and serve the same purpose, owning both may not provide much additional diversification.

Compare their:

• Underlying indexes
• Holdings
• Expense ratios
• Trading costs
• Liquidity
• Tax circumstances
• Tracking history

Lower cost alone should not determine the decision, but expenses remain important. The SEC notes that fund fees reduce investment returns, and layered products may produce additional costs. Review the fund’s fee table and expense disclosures.

Diversify across asset classes

Owning more stock ETFs does not necessarily create broader diversification.

Depending on your goals and risk tolerance, meaningful diversification may involve exposure to different asset classes or markets rather than several similar U.S. equity funds.

Avoid collecting ETFs without defined roles

A new ETF may sound attractive because it follows a popular industry or investment theme. Before buying it, determine whether your current funds already contain the same companies.

If you are beginning with limited capital, focus first on a clear strategy for investing with a small amount of money instead of accumulating numerous overlapping funds.

Review the portfolio as a whole

Analyze all accounts together when possible. Rebalancing one account without considering the others can leave overall exposure unchanged.

Consider taxes before selling

Selling an ETF in a taxable account can create capital gains or losses and other tax consequences.

Do not sell solely to achieve a visually cleaner portfolio. Compare the potential improvement with transaction costs, taxes, and your long-term plan. Consider consulting a qualified tax professional before making a significant taxable change.

When Keeping Overlapping ETFs May Make Sense

There are situations in which keeping similar funds can be reasonable.

Large unrealized gains

Replacing a position in a taxable account might generate a tax bill that outweighs the benefit of simplifying the portfolio immediately.

Different account choices

An employer retirement plan may offer only a limited selection of funds. You may hold a similar but lower-cost fund in another account because the preferred option is unavailable in the workplace plan.

Intentional investment tilt

You may deliberately combine a broad-market ETF with a sector, value, growth, or small-cap ETF.

That overlap represents an active portfolio decision, provided you understand the additional concentration.

Gradual portfolio transition

Instead of selling an older ETF immediately, an investor might direct new contributions toward the preferred fund and allow the portfolio to change over time.

Tax-loss harvesting considerations

Some investors temporarily use comparable—but not identical—funds as part of a tax-management strategy. Because tax rules can be complex, professional guidance may be appropriate.

Common ETF Overlap Mistakes

Assuming more funds always mean more diversification

Ten ETFs can still produce a concentrated portfolio if most of them own the same large companies.

Comparing only fund names

Terms such as “growth,” “innovation,” “technology,” and “large cap” may describe funds with highly similar holdings.

Checking only the top holding

A single repeated company does not reveal the full picture. Review multiple holdings, position weights, and sector exposure.

Ignoring position sizes

A 50% overlap between two tiny positions may matter less than a 15% overlap between funds representing most of your portfolio.

Focusing only on stocks

Two funds with different holdings may still behave similarly because they share the same sector, investment style, or geographic exposure.

Making changes too frequently

ETF holdings and market weights naturally change. Constantly restructuring a portfolio to minimize every percentage of overlap may create unnecessary trading, costs, and taxes.

ETF Overlap Review Checklist

Use this checklist when evaluating your portfolio:

• List every ETF across all accounts.
• Record the value and portfolio percentage of each position.
• Identify the intended role of every fund.
• Compare indexes and investment objectives.
• Review the top 10–20 holdings.
• Compare the full holdings where available.
• Check sector, style, and geographic allocations.
• Estimate exposure to repeated large positions.
• Identify funds with duplicate roles.
• Review expense ratios and other costs.
• Consider taxes before selling.
• Confirm that any remaining overlap is intentional.
• Revisit the analysis periodically or after major portfolio changes.

FINRA recommends starting investment decisions with your goals, time frame, and ability to tolerate risk rather than selecting products in isolation. Its investing basics guidance provides additional context for developing an overall plan.

Frequently Asked Questions

What does ETF overlap mean?

ETF overlap means that two or more exchange-traded funds own some of the same securities. It may also refer to similar sector, geographic, or investment-style exposure.

Is 50% ETF overlap too high?

A 50% overlap figure is significant enough to investigate, but it is not automatically unacceptable. Consider each fund’s position size, purpose, underlying holdings, and effect on the entire portfolio.

Can two ETFs track different indexes and still overlap?

Yes. Different indexes can include many of the same companies, particularly among large U.S. stocks.

Is zero ETF overlap ideal?

Not necessarily. Eliminating all overlap can make a portfolio unnecessarily complex. The objective should be intentional diversification rather than a perfect zero-overlap score.

How often should I check ETF overlap?

Consider reviewing overlap during a regular portfolio review, after buying a new fund, or when an ETF changes its strategy or underlying index. Constant monitoring is generally unnecessary for a long-term portfolio.

What is the best ETF overlap tool?

There is no single tool that is best for every investor. Compare results from a reputable overlap or ETF-comparison tool with current holdings published by the official fund provider.

Does ETF overlap increase fees?

Overlap does not directly increase an individual ETF’s expense ratio. However, owning unnecessary or layered funds can complicate the portfolio and may expose you to costs without adding meaningful diversification.

Final Thoughts

ETF overlap is common and does not need to be eliminated completely.

The real risk is not overlap itself—it is unrecognized concentration. Several funds can create the appearance of diversification while repeatedly exposing your money to the same companies, industries, or investment styles.

Check what your ETFs own, understand the role of each fund, measure their effect on your entire portfolio, and keep only the overlap that supports your strategy.

A simpler portfolio is not always better, but every holding should have a clear purpose.

This article is for educational purposes only and does not constitute investment, tax, or financial advice. Investments involve risk, including the possible loss of principal. Consider your circumstances and consult qualified professionals when necessary.