Nasdaq-100 / QQQ

01What it is

The Nasdaq-100 is an index of the hundred largest non-financial companies listed on the Nasdaq exchange, weighted by market value. Because the Nasdaq is where most large technology companies list, the index is dominated by technology, communication services and consumer companies with a growth profile. Banks and insurers are excluded by rule.

QQQ is the ETF that owns those hundred stocks in index proportion. It is one of the most actively traded securities in the world and the instrument most traders mean when they say 'tech' or 'growth'.

Its concentration is even heavier than the S&P 500's: a handful of the largest companies routinely make up close to half the index. When they move, QQQ moves, whatever the other ninety do.

02Why it exists

The index exists to represent the Nasdaq's largest companies as a group, and it became important because that group came to define a style: growth. As investors increasingly sorted the market into 'growth' and 'value', QQQ became the cleanest way to own or trade the first.

It also exists as a sentiment gauge. Growth companies are valued on expectations about the future, and expectations are what move most when interest rates, confidence or risk appetite change. QQQ is where those changes are felt first and hardest.

03How it is measured or observed

QQQ is read against the broad market and against the things that move growth valuations:

• QQQ vs SPYThe growth-versus-broad-market ratio. Rising = growth leading; falling = growth lagging. The single most watched relative line in the market.
• Top holdings' weightThe share of the index held by the largest five or ten companies. The higher it is, the more QQQ is a bet on a few names.
• Interest rates (10-year yield)Growth stocks are valued on distant earnings, so rising long-term yields tend to hurt them more than value stocks. QQQ often moves opposite to yields on rate-driven days.
• Semiconductor indexChips lead technology; the semiconductor group often leads QQQ up and down.
• Equal-weight Nasdaq-100The same hundred stocks counted equally. When it lags QQQ, the giants are carrying the index.
• VolatilityQQQ is typically more volatile than SPY; its implied volatility (the VXN) runs higher than the VIX.

04How professionals read it

Professionals read QQQ first as a ratio. QQQ over SPY rising tells them growth is leading and the market is paying for the future — usually a risk-on, falling-or-stable-rates environment. The ratio falling tells them the opposite: value, cyclicals or defensives are leading and growth is being sold.

They watch its relationship with yields closely. On days when the 10-year yield jumps, they expect QQQ to underperform; when it falls, to outperform. When that relationship breaks — QQQ rallies through rising yields — something else is driving, usually earnings or a specific catalyst in the giants.

They also treat it as the index of the leaders. Because its largest members are the market's largest companies, QQQ's behaviour at the open and the close sets the tone for thousands of growth and technology stocks. A trader in a semiconductor name is really trading QQQ with extra volatility.

05What strength looks like

QQQ strength looks like growth leadership: the QQQ/SPY ratio rising, semiconductors leading, pullbacks shallow and bought, and the largest names making highs together — ideally with the equal-weight version keeping pace, so the leadership is broad inside the index.

06What weakness looks like

QQQ weakness looks like growth being sold: the ratio falling, semiconductors lagging, rallies that fail, and the giants falling harder than the market. It often coincides with rising long-term yields or a shift toward defensive leadership.

07What a divergence looks like

The divergence worth watching is QQQ making new highs while its equal-weight version and the semiconductor group do not. The index is being carried by its largest members alone — the narrowest possible form of growth leadership, and the most fragile.

08What it means for an investor

For an investor QQQ is a concentrated growth holding, not a diversified one. It has delivered strong long-term returns and deep drawdowns — its decline after 2000 took years to recover. Owning it means accepting that you are betting on the continued leadership of a small number of large growth companies.

It pairs naturally with the interactive on this site: the same $100-a-month plan into a growth index has historically produced higher highs and deeper lows than the S&P 500. Which you prefer depends on the decade you can sit through.

09What it means for a trader

For a trader QQQ is the tape to watch for any growth or technology stock. A breakout in a software name on a day QQQ is losing VWAP is swimming upstream. The Advanced program reads QQQ and SPY side by side before the first trade of the day.

It is also the cleaner instrument on rate-driven days: when yields are the driver, QQQ's reaction is faster and larger than SPY's, which makes it both the better read and the riskier trade.

10What it cannot tell you

• It is not 'the tech sector'. It excludes financials by rule, includes large consumer and communication companies, and misses technology companies listed elsewhere.
• Its moves are dominated by a few giants. A strong QQQ does not mean a strong average growth stock.
• Growth leadership can persist for years or reverse in a quarter. The ratio describes; it does not forecast.
• Higher long-term returns came with larger drawdowns. Past leadership is not a guarantee.

11What is happening right now

How to check this yourself today

• Chart QQQ divided by SPY over six months. Is the ratio rising or falling?
• Compare QQQ with its equal-weight version (QQQE) over one month.
• Note the 10-year yield's direction over the last two weeks and whether QQQ moved opposite to it.
• Check the semiconductor ETF (SMH or SOXX) against QQQ — are chips leading?

12Visual market example

The growth-versus-market picture in one chart: QQQ leads while rates are stable, then lags as yields rise. The S&P barely notices. A trader in growth names who reads only the S&P would have missed the change entirely.

13Test your understanding

Read the chart the way you would before a trade. Pick the answer, then read why.

14Key takeaways

1. QQQ is the hundred largest non-financial Nasdaq companies, heavily concentrated in a few giants — the growth barometer.
2. Read it as a ratio against SPY: rising means growth is leading.
3. It is the most rate-sensitive major index; watch the 10-year yield beside it.
4. Check equal-weight and semiconductors to see whether growth leadership is broad or giant-only.
5. Higher long-term returns have come with deeper drawdowns. Know which you are signing up for.

15Related concepts

• Major Indexes & ETFsS&P 500 / SPY
• Sector IntelligenceTechnology
• Market OverviewLeadership / Weakness
• Trading ContextCorrelation with QQQ / SPY

16Learn it in class