S&P 500 vs Nasdaq-100 Holdings Overlap: 86 of 100 Repeat

I see a lot of Canadian investors holding an S&P 500 ETF and a Nasdaq-100 ETF side by side, usually something like VFV or ZSP next to ZQQ or XQQ.

The reasoning sounds sensible enough. The S&P 500 gives broad U.S. exposure, and the Nasdaq-100 is expected to layer on technology and growth. I made the same assumption for a while myself.

Then I actually ran the overlap between the two. Most of what I thought was "adding tech" was money landing right back on companies I already owned through my S&P 500 position.

The S&P 500 is not an equal-weighted basket of 500 companies. It is weighted by market capitalization, so the largest companies receive the largest allocations. As technology companies have grown into the largest companies in the U.S. market, they have also grown into the largest positions in the S&P 500.

Adding a Nasdaq-100 ETF does bring in a handful of companies you did not previously own. But most of the money you put into it increases your stake in companies your S&P 500 ETF already holds.

You are not buying technology for the first time.

You are buying more of it.

Many investors think of the S&P 500 and Nasdaq-100 as two different parts of the market. The S&P 500 is the broad U.S. market. The Nasdaq-100 is the technology allocation.

That distinction is increasingly artificial.

The Nasdaq-100 is not formally a technology index. It holds 100 of the largest non-financial companies listed on the Nasdaq exchange. It became associated with technology because many of the largest technology and growth companies chose to list there and eventually came to dominate the index.

The S&P 500 selects large U.S. companies from both Nasdaq and the New York Stock Exchange. As Apple, Microsoft, Nvidia, Amazon, Alphabet, Meta and Tesla (a.k.a. the MAG 7) became some of the largest businesses in the country, they also became some of the largest holdings in the S&P 500.

Several of these companies are no longer even reported inside the official Information Technology sector. Alphabet and Meta were moved into Communication Services in 2018, while Amazon and Tesla are classified as Consumer Discretionary. That can make the S&P 500 appear less technology-heavy than it really is.

Investors reach for the Nasdaq-100 believing they're adding a separate technology allocation. Most of those companies are already among the largest positions in their S&P 500 ETF.

The Nasdaq-100 does not give an investor technology exposure that was previously missing. It mainly changes the weights of technology-driven companies the investor already owns.

The S&P 500 gets described as a broad market index, and it is broad in the sense that it holds roughly 500 leading U.S. companies from every major economic sector.

That does not mean those companies are represented equally.

As of July 1, 2026, information technology represented 37.41% of SPY, the ETF most Canadians picture when they say "the S&P 500." Communication services added another 9.96%, and consumer discretionary added 9.41%, largely the Alphabet, Meta, Amazon and Tesla weight described above. Whether you hold SPY directly, or a Canadian-listed wrapper like VFV, ZSP or XUU, you are holding the identical underlying securities in the identical proportions, so every figure here applies to your account regardless of which ticker sits in your TFSA or RRSP.

Looking only at the official technology-sector percentage understates how much of the index is actually driven by technology businesses.

The largest SPY holdings as of July 1, 2026:

The Magnificent Seven alone represented approximately 32.15% of the S&P 500. That means roughly $32,150 of a $100,000 S&P 500 investment was already allocated to Nvidia, Apple, Microsoft, Amazon, Alphabet, Meta and Tesla, before a single dollar touched a Nasdaq-100 fund.

An investor does not need to add the Nasdaq-100 to gain meaningful exposure to these businesses. They are already the companies with the greatest influence over how the S&P 500 performs.

The S&P 500 rebalances its weights continuously as prices move, with no committee needed to decide that Nvidia deserves a bigger slice. As a stock's market value rises relative to the other 499, its weight in the index simply rises with it. That is the entire mechanism behind how technology came to dominate a fund most people describe as "broad market."

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The index uses a modified market-capitalization weighting system, so larger companies generally get larger allocations, with limits applied during rebalancing to cap runaway concentration.

Technology and growth still dominate the construction, but the mandate is broader than that. Consumer, health-care, industrial and utility names all qualify too.

The Nasdaq-100 also excludes financial companies entirely, and it selects companies partly based on where their shares are listed rather than by trying to represent the whole U.S. economy. A large company on the New York Stock Exchange does not qualify just because it is large, while a large eligible non-financial company on Nasdaq may qualify even if it is smaller. That is why the index holds names like Costco, PepsiCo, Starbucks, Marriott, Amgen and Intuitive Surgical alongside Nvidia, Apple and Microsoft.

The gap goes well beyond the headline technology number. Here is the full sector breakdown for both indices:

It's tempting to write that gap off as "the Nasdaq-100 just doesn't hold financials." That's true, but it isn't the whole explanation. Strip financials and real estate out of SPY entirely and rescale what's left, and technology only climbs to about 43% of the total. QQQ's 58.65% is still well beyond that.

Technology, communication services and consumer discretionary together make up roughly 84% of QQQ, against about 56% of those same three sectors in SPY. Health care, industrials, consumer staples, utilities and materials, sectors that carry real weight in the S&P 500, shrink to rounding errors once you're inside the Nasdaq-100.

Whether you access QQQ directly or through a Canadian-hedged version like ZQQ or XQQ, that same sector tilt travels with the fund.

A name-by-name match of the two current holdings lists identifies 86 securities held in both the S&P 500 and the Nasdaq-100. Only 16 Nasdaq-100 securities sit outside the S&P 500. The security count runs to 102 rather than a clean 100 for two reasons: Alphabet's dual share classes both qualify, and Honeywell currently shows up twice, as Honeywell International and as the newly spun-off Honeywell Aerospace, while the index transitions between the two.

The overlap includes most of the names investors associate with the Nasdaq-100 in the first place:

Buying QQQ (or ZQQ, or XQQ) after you already own an S&P 500 ETF does not introduce these companies to your portfolio. It increases the amount you have invested in them.

Buying more VFV would achieve the same result if you want to double down on these companies while adding more diversification with financials.

Matching a full Nasdaq-100 holdings file against S&P 500 holdings name by name turns up 16 Nasdaq-100-exclusive securities:

Two of these are worth a second look before you file them under "new exposure." Marvell Technology is the single largest name on the list and a genuine surprise: it's a major AI and data-center chipmaker, the kind of company an investor would assume sits in the S&P 500 alongside Nvidia and AMD, and it currently doesn't. Honeywell Aerospace, on the other hand, isn't really a new company at all. It's Honeywell's aerospace unit showing up as its own line item mid-spinoff, alongside the still-listed Honeywell International. Treat that one as a bookkeeping artifact of the split rather than a new business you've gained.

There's also a small piece of Canadian irony buried in that table. Shopify, one of the largest companies to ever come out of Canada, only shows up in this list because it is Nasdaq-listed and not currently in the S&P 500. A Canadian investor buying QQQ purely to get more American tech exposure is, in part, buying back a company built in Ottawa.

These are not insignificant businesses. The list includes a top-tier semiconductor name in Marvell, a leading semiconductor-equipment maker in ASML, a major chip-architecture company in Arm, international e-commerce names in Shopify and MercadoLibre, and newer artificial-intelligence infrastructure names in Astera Labs, Nebius and CoreWeave. The Nasdaq-100 also opens the door to international companies and eligible American depositary receipts that would not necessarily qualify for the S&P 500.

There is genuine new exposure here.

It is simply much smaller than most investors assume.

The 16 Nasdaq-100-exclusive holdings collectively represented approximately 5.79% of QQQ. The remaining 94% or so was allocated to securities already held in the S&P 500.

For a $10,000 investment in QQQ:

Most of the investment increases the amount allocated to companies you already own. The new companies exist, but that is not where most of the money goes.

The effect shrinks further once QQQ becomes a smaller satellite position rather than a standalone holding. Say you build an 80/20 core-satellite portfolio:

The Nasdaq-exclusive positions now represent approximately:

20% × 5.79% = 1.16% of the overall portfolio

For every $100,000 invested, only about $1,158 goes toward companies gained exclusively through the Nasdaq-100. The remaining $18,842 of that Nasdaq-100 allocation mostly reinforces companies already sitting in the S&P 500 sleeve.

That does not make the allocation wrong. It tells you what the allocation is actually doing.

Investors sometimes describe holding both indexes as doubling down on technology. That is directionally true, but it overstates the effect on any single name.

You are not doubling every major technology position. The weights of the very largest companies are actually fairly close between SPY and QQQ:

SPY figures are as of July 1, 2026. QQQ figures for the first eight rows are as of June 30, 2026; AMD, Intel, Applied Materials, Lam Research and KLA are as of June 26, 2026, the most recent public data available at the time of writing.

The individual Magnificent Seven names above barely move between SPY and QQQ. The sector exposure behind them does not stay nearly as close:

Technology, communication services, and consumer discretionary combined make up roughly 84% of QQQ against about 56% of SPY. Health care, industrials, consumer staples, utilities and materials, sectors that carry real weight in the S&P 500, are close to rounding errors inside the Nasdaq-100.

The Magnificent Seven represented approximately 32.15% of SPY and 34.79% of QQQ. Rather than looking only at a 50/50 blend, it's worth walking the full range of possible splits, from all S&P 500 to all Nasdaq-100, to see how much that actually moves:

"New-to-Nasdaq-100 weight" is the 5.79% of QQQ made up of the 16 exclusive securities from earlier, scaled down by how much Nasdaq-100 you're actually holding.

Walk the entire spectrum from 100% S&P 500 to 100% Nasdaq-100 and the Magnificent Seven's share of the portfolio moves from 32.15% to 34.79%, a swing of 2.64 percentage points. That's the full range. Going all the way to 100% QQQ, abandoning the S&P 500 completely, still doesn't push Magnificent Seven exposure past 35%. And the exposure you don't already own through the S&P 500 tops out at 5.79%, even at that extreme.

There is no blend of these two funds that meaningfully changes how loaded up on the Magnificent Seven your portfolio is. That number barely moves. What actually shifts is the layer underneath them, the semiconductors, software and growth names further down the list.

The more noticeable shift shows up below the very largest names. Micron Technology goes from 1.81% of SPY to 5.63% of QQQ, more than three times the weight. The rest of the semiconductor group follows the same pattern: AMD roughly triples from 1.37% to 3.83%, Intel more than triples from 0.93% to 2.90%, and Applied Materials, Lam Research and KLA each carry close to three times their SPY weight inside QQQ. Add heavier exposure to software, cybersecurity and other growth-oriented businesses on top, and that is where the real gap between the two funds lives.

That is the real portfolio construction decision hiding inside "I'll add some Nasdaq-100 for growth." You are giving more weight to a specific group of companies and industries that already have significant representation in your S&P 500 holding.

Is there a meaningful impact to add the Nasdaq-100?

Market-cap weighting has a built-in, momentum-like effect. As a company becomes more valuable, its allocation inside the index generally rises with it.

Nvidia is the clean example. As its market capitalization climbed, its weight in the S&P 500 climbed too. Nobody holding an S&P 500 ETF had to identify Nvidia early or bolt on a separate technology fund later. The index quietly increased the position on their behalf.

That is part of what makes market-cap weighting effective. Winners get to grow without requiring anyone to predict them in advance.

It also creates concentration. When several companies from related industries become the largest companies in the market, the S&P 500 naturally becomes more dependent on those same companies. Layering the Nasdaq-100 on top means stacking a second market-cap-weighted index over one that is already leaning hard on many of the same market leaders.

Adding QQQ does not just increase your exposure to Nasdaq companies. It reduces the proportionate influence of companies that only exist in the S&P 500.

Some of the largest S&P 500 companies currently missing from the Nasdaq-100:

The Nasdaq-100's exclusion of financial companies means it holds none of JPMorgan, Bank of America, Goldman Sachs, Morgan Stanley, Visa or Mastercard. Adding QQQ doesn't sell those positions out of your S&P 500 sleeve, but it shrinks their share of your combined portfolio.

You are shifting capital away from financials, health care, energy and defensive consumer businesses on a relative basis, and directing more toward technology, semiconductors and growth.

That may be exactly what you want. It should still be a decision you're making on purpose rather than one that happens by default because two ETFs sounded more diversified than one.

None of this means combining the S&P 500 and Nasdaq-100 is a mistake.

Owning both can make sense when the decision is intentional.

You might want more exposure to semiconductors, artificial intelligence infrastructure, software and other technology-driven businesses, believing they'll keep outgrowing the broader market. You may want access to Nasdaq-listed international companies or newer names that haven't entered the S&P 500 yet.

An 80/20 split, S&P 500 as the core with Nasdaq-100 as a growth tilt, is a reasonable way to build that. If a single-ticket option feels simpler, an all-in-one equity ETF that already holds global markets is worth comparing against a two-fund SPY-and-QQQ combination before you commit to either.

That is a reasonable portfolio construction decision.

It is not the same as diversification.

Diversification is not measured by the number of ETFs sitting in your account. It is measured by the underlying companies, industries, geographies and economic risks you actually own.

Holding SPY and QQQ gives you two ticker symbols. It does not give you two genuinely different portfolios, because most of QQQ is already inside SPY. The second ETF mainly changes the weights.

That distinction matters because investors can end up believing they've built a more diversified portfolio when they've actually made it more concentrated. The portfolio may perform extremely well while technology and semiconductor names lead the market, and it may swing harder when those names fall out of favour.

Invesco itself states that QQQ is non-diversified and may carry greater volatility than a broader fund, warning that sector-concentrated holdings can be more exposed to market swings. The Canadian-listed Nasdaq-100 wrappers carry the same underlying concentration and the same warning, even if the fine print sits with a different fund company.

Concentration on its own is not the problem. Concentration you don't recognize is.

Before adding the Nasdaq-100 to an S&P 500 position, ask four questions:

→ Which companies am I gaining that I do not already own?
→ How much of my investment will actually go into those new companies?
→ Which existing companies and industries am I increasing?
→ Do I intentionally want less relative exposure to financials, health care, energy and other parts of the market?

The current numbers give a fairly clear answer. You gain 16 Nasdaq-100 securities that aren't in the S&P 500, and they collectively represent only about 5.8% of QQQ. Roughly 94% of a Nasdaq-100 investment goes toward securities you already hold through the S&P 500.

Adding the Nasdaq-100 isn't primarily about gaining new companies. It's about reweighting your portfolio toward companies and themes you already own. There's nothing wrong with making that call. Technology, semiconductors and large growth companies may keep producing strong returns, and the Nasdaq-100 may keep outrunning the broader market.

Just be clear about what you're buying.

You are not adding technology to a portfolio that was missing it. The S&P 500 already owns the leading technology companies and automatically gives its largest allocations to the biggest market winners.

By adding the Nasdaq-100, you are deliberately asking those same companies, and the ecosystem around them, to carry even more of your portfolio.