NASDAQ 100 and S&P 500 Overlap: Analyzing the Intersection of Two Major Indices

The Nasdaq-100 and S&P 500 overlap heavily. Roughly 85 of the Nasdaq-100's 100 companies also sit in the S&P 500, and those shared names make up around 94% of QQQ by weight. Owning both VOO and QQQ mostly doubles your bet on a handful of mega-cap tech stocks rather than diversifying.

Key takeaways

• The large majority of Nasdaq-100 members are also in the S&P 500. One July 2026 holdings analysis counted 86 of the roughly 100 Nasdaq-100 securities inside the S&P 500; Nasdaq's own reporting frames it as about 16 names sitting outside, or roughly 84. Call it the mid-80s either way.
• Overlap by weight is far higher than overlap by count. Around 94% of QQQ's assets sit in companies the S&P 500 also holds, and Morningstar puts the QQQ weight that VOO does not already cover at only about 4%.
• The same seven stocks drive both indexes. The Magnificent Seven made up roughly 38% to 40% of QQQ in mid-2025 and around 32% to 35% of the S&P 500 through late 2025.
• Holding VOO and QQQ together is concentration, not diversification. You are buying the same Apple, Nvidia, Microsoft, Alphabet, and Amazon shares twice, just in different proportions.
• If you want real diversification, the differences that matter are outside the top holdings: small caps, value, international, bonds, and other sectors.

How much do the Nasdaq-100 and S&P 500 actually overlap?

Two numbers tell the story, and they are very different.

By company count, the overlap is large but not total. A July 2026 holdings breakdown from Smart Investing Journey found 86 of the roughly 100 Nasdaq-100 securities also held in the S&P 500. Nasdaq's own commentary describes it from the other direction, with about 16 Nasdaq-100 names sitting outside the S&P 500, which lands near 84. The exact figure moves a little because Alphabet carries two share classes and index membership shifts each quarter, so treat the mid-80s as the honest range rather than a fixed percentage.

By weight, the overlap is much tighter. Because both indexes are market-cap weighted, the giants at the top dominate. That same July 2026 analysis found roughly 94% of QQQ's assets sit in securities the S&P 500 also holds, leaving under 6% that is genuinely unique to the Nasdaq-100. Morningstar reached a similar conclusion, noting only about 4% of QQQ by weight is not already inside a fund like VOO.

The takeaway: the handful of Nasdaq-100 names that are NOT in the S&P 500 are mostly smaller foreign-domiciled or financial-adjacent companies that carry little weight. The stocks that move QQQ are the same stocks that move the S&P 500.

Top shared holdings and their weight in each index

Here is where the overlap becomes concrete. The largest positions are nearly identical across both indexes, which is why they rise and fall together.

Source: Smart Investing Journey holdings analysis, SPY weights as of July 1, 2026 and QQQ weights as of June 30, 2026. Weights drift daily with price, so read these as a snapshot, not a live quote.

Add the rest of the Magnificent Seven (Meta, Tesla) plus Broadcom and the concentration is stark. The Magnificent Seven alone accounted for roughly 32% to 35% of the S&P 500 through late 2025 and closer to 38% to 40% of QQQ in mid-2025, per Invesco and multiple index trackers. QQQ is simply a more concentrated slice of the exact same leadership.

Are you actually diversified if you hold both VOO and QQQ?

Probably less than you think. This is the practical point for a FatFIRE portfolio.

When you buy VOO you already own every one of those mega-cap tech names, at meaningful weight. Layering QQQ on top does not add new companies in any material way. It just increases your exposure to the stocks you already hold most. You are not spreading risk across two different markets. You are tilting harder into one bet.

That tilt has consequences in both directions:

• In a tech-led bull run, the doubled-up exposure amplifies your gains, which is exactly why the pairing feels good on the way up.
• In a tech drawdown or a rotation into value, small caps, or international, the same concentration amplifies your losses. A regulatory action, an AI capex reset, or a single earnings miss from one $3 trillion company can drag both funds at once.

None of this makes QQQ bad. It makes the VOO-plus-QQQ combination redundant. If your goal in adding QQQ was diversification, it did not deliver that. If your goal was a deliberate overweight to large-cap growth, then it is doing its job, and you should size it knowing that is what you own.

For genuine diversification, the additions that actually change your risk profile sit outside the top of these indexes: small-cap or mid-cap exposure, value factors, international and emerging markets, bonds, and sectors that barely register in either index, such as utilities, energy, and real estate.

The practical takeaway

If you hold both VOO and QQQ, you do not have two diversified holdings. You have one core S&P 500 position and a concentrated large-cap tech amplifier stacked on top of it. That can be a reasonable choice, but make it on purpose.

Three questions worth answering before your next rebalance:

1. What is my true combined weight in the Magnificent Seven once I stack both funds? It is likely higher than you would pick from scratch.
2. Am I holding QQQ for a specific growth tilt, or did I add it believing it diversified me? If the latter, the data says otherwise.
3. Where is my real diversification coming from? If the answer is only large-cap US stocks, you have a concentration you may not have chosen deliberately.

For a side-by-side on which single fund fits your goals, see our head-to-head S&P 500 vs QQQ comparison. For the long-run performance question, see S&P 500 vs Nasdaq-100 over the long term. If you are weighing whether concentrated bets are worth it at all, beating the S&P 500 is a useful reality check. And for the broader picture of how the index is built and behaves, start with our S&P 500 hub.