UK screens quote the S&P 500 for broad US equities and the FTSE 100 for London large caps. The Nasdaq 100 sits beside them as the best-known tech-heavy US index — a basket of the largest non-financial companies listed on the Nasdaq exchange. For beginners, literacy means knowing what is inside it, how it differs from the S&P 500, and why London desks watch it when growth stocks and US rates move together.
This article is educational index literacy for UK traders. It is not a recommendation to buy or sell Nasdaq futures, ETFs or single names. For the broader US benchmark see what the S&P 500 is and why UK traders watch it, and for the home tape what the FTSE 100 is.
What the Nasdaq 100 is
The Nasdaq 100 tracks roughly the 100 largest non-financial companies listed on Nasdaq by modified market capitalisation. Mega-cap technology, consumer internet, semiconductors and related growth names dominate the weight. Financials are excluded by design — that is one reason it feels different from the S&P 500, which includes banks and a wider sector mix. Rebalances and corporate actions change membership over time; the educational point is concentration in growth and tech-adjacent cash flows, not a static ticker list.
Samuel & Co Trading’s assessment is that beginners should say “Nasdaq 100” when they mean this index, and not confuse it with the Nasdaq Composite, which is a much broader exchange-wide measure.
How it differs from the S&P 500
Both are US large-cap stories. The S&P 500 is broader across sectors and includes financials, energy, industrials and staples in meaningful weight. The Nasdaq 100 is more concentrated in technology and growth. On days when megacap tech leads, the Nasdaq 100 can outpace the S&P; on days when value, energy or banks lead, the gap can reverse. UK traders who only watch “the US market” as one number miss that composition split.
Why London watches the session
US cash equities open at 14:30 or 15:30 UK time depending on daylight saving. Futures and related products trade earlier, so London mornings already see Nasdaq-linked price discovery. Into the US open, UK desks use the Nasdaq 100 as a thermometer for global risk appetite, especially when bond yields, the dollar and megacap earnings narratives are in play. Futures and CFDs on many UK platforms quote Nasdaq-linked symbols; know whether you are looking at the cash index, a futures contract or a CFD.
Growth stocks and the rates channel
Because the index is growth-heavy, it often reacts sharply when real yields and discount-rate narratives shift. Higher real yields can pressure long-duration equity valuations even if near-term earnings hold; softer real yields can do the opposite. That link is educational macro literacy — see the companion framing on how higher real yields pressure growth stocks when reading rates weeks — not a timing system.
Common mix-ups
Do not confuse the Nasdaq 100 with the Nasdaq Composite. Do not assume every Nasdaq-listed stock is in the 100. Do not treat a futures print overnight as identical to the cash index close. Do not ignore concentration risk: a handful of megacaps can drive a large share of index moves.
A clean UK habit
On a busy US equity day: note whether the Nasdaq 100 is leading or lagging the S&P 500; glance at whether megacap tech headlines or broader sector rotation explain the gap; and check whether yields and the dollar moved in the same window. That three-line checklist improves how you read UK afternoon risk colour without converting every tick into a trade.
If you want a structured look at how you process index concentration and session timing, a free traders assessment can highlight sizing and focus habits without personal advice.
Conclusion
The Nasdaq 100 is a tech-heavy US large-cap index that UK traders watch beside the S&P 500 and the FTSE 100. Composition, concentration and the rates channel explain why it can diverge from broader US benchmarks. Educational framing only — not a buy or sell recommendation.
