$100 put into a Nasdaq-100 fund at the end of September 2016 was worth $668 ten years later. That counts dividends, the cash companies pay their shareholders. The same $100 in an S&P 500 fund grew to $413. In a fund that holds shares from around the world, it reached $320.
An index is a list of shares with rules for how much of each to count. An index fund buys those shares, so its return follows the index. This guide compares three of the best-known indices: what each holds, what funds tracking them returned and how far each fell.
What is the difference between the S&P 500, the FTSE All-World and the Nasdaq-100? The S&P 500 holds 500 large US companies. The FTSE All-World holds 4,204 large and mid-sized companies from 49 countries. The Nasdaq-100 holds 100 large companies listed on the Nasdaq stock exchange, leaving out banks and other financial firms.
A world index is still mostly American. US companies made up 62.28% of the FTSE All-World on 30 September 2026.
The Nasdaq-100 is the most concentrated. Its ten largest holdings made up 46.86% of the index on 30 September 2026. That compares with 39.3% for the S&P 500 on 6 October and 24.81% for the FTSE All-World on 30 September.
Over the ten years to 30 September 2026, a Nasdaq-100 fund returned 20.9% a year with dividends counted. An S&P 500 fund returned 15.2% and a world fund 12.3%. The Nasdaq-100 fund also swung the most.
What the S&P 500, the FTSE All-World and the Nasdaq-100 hold
All three indices weight each company mainly by its market value, the share price times the shares available to trade. So the biggest companies count the most.
The S&P 500 is run by S&P Dow Jones Indices. It holds 500 large US companies. A company must be based in the US to join. What Is the S&P 500? explains the rules.
The FTSE All-World is run by FTSE Russell, part of the London Stock Exchange Group. It holds 4,204 large and mid-sized companies from developed and emerging markets. Emerging markets are less developed economies, such as China and India.
The Nasdaq-100 is run by Nasdaq. It holds 100 of the largest companies listed on the Nasdaq stock exchange, from the US and abroad. Financial companies are left out by rule. Nasdaq also caps the weights of its largest companies.
Index | Run by | What it holds | Countries | Ten largest holdings | Largest sector | Data date |
|---|---|---|---|---|---|---|
S&P 500 | S&P Dow Jones Indices | 500 large US companies (503 share lines) | US only | 39.3% | Information Technology 40.18% (GICS) | 6 October 2026 |
FTSE All-World | FTSE Russell | 4,204 large and mid-sized companies | 49, with the US at 62.28% | 24.81% | Technology 36.11% (ICB) | 30 September 2026 |
Nasdaq-100 | Nasdaq | 100 large non-financial companies listed on Nasdaq (101 share lines) | US and other countries | 46.86% | Technology 68.01% (ICB) | 30 September 2026 |
Source: State Street (SPY data); FTSE Russell; Nasdaq; YX Insights
The table sets the three side by side. The S&P 500 figures come from State Street, which runs SPY (the S&P 500 exchange-traded fund, or ETF). The other two come from each index provider's factsheet.
The ten largest holdings made up 46.86% of the Nasdaq-100 and 39.3% of the S&P 500. In the FTSE All-World, they made up 24.81%. The S&P 500 figure is from 6 October. The other two are from 30 September.
The sector figures use two different systems. S&P uses the Global Industry Classification Standard (GICS), which puts Alphabet and Meta outside technology. FTSE Russell and Nasdaq use the Industry Classification Benchmark (ICB), which counts them as technology. So the sector shares are not like for like.
Where the FTSE All-World invests: country weights
Source: FTSE Russell; YX Insights
Chart 1 shows the FTSE All-World by country on 30 September 2026. The US made up 62.28%. Japan came next at 6.06%. The UK was 3.06%. The other 42 countries outside the top seven made up 16.87% together.
So a world index spreads across 49 countries, but 483 US companies carry most of its weight. Its top holdings overlap with the S&P 500's too. Nine of the FTSE All-World's ten largest holdings were also in the S&P 500's top ten on 6 October. The odd one out was Taiwan Semiconductor Manufacturing, at 1.79%.
S&P 500 vs Nasdaq-100: the same names, different weights
The Nasdaq-100 is a narrower slice of mostly the same big names. All ten of its largest holdings were also in the S&P 500 on 6 October 2026.
The difference is the weight further down the list. Nvidia, Apple and Microsoft weigh about the same in both. They made up 21.52% of the Nasdaq-100 on 30 September 2026 and 21.66% of the S&P 500 on 6 October.
The next names differ. Micron and Advanced Micro Devices, two chipmakers, made up 9.23% of the Nasdaq-100. In the S&P 500, they made up 3.33%. Technology companies made up 68.01% of the Nasdaq-100 under the ICB system. Financial companies made up 0%.
S&P 500 vs FTSE All-World vs Nasdaq-100 returns, 2016 to 2026
An index cannot be bought directly, so this guide uses three ETFs as stand-ins. An ETF is a fund whose shares trade on a stock exchange:
SPY (the S&P 500 ETF);
QQQ (the Nasdaq-100 ETF);
VT (Vanguard Total World Stock ETF).
VT tracks the FTSE Global All Cap Index. That index adds smaller companies, with 10,138 holdings at the end of June 2026. So VT is close to the FTSE All-World, but not the same. What Is an Index Fund? explains how a fund follows its index.
Source: YX Insights
Chart 2 starts $100 in each fund on 30 September 2016, with dividends counted. By 30 September 2026, QQQ had reached $668, or 20.9% a year. SPY reached $413, or 15.2% a year. VT reached $320, or 12.3% a year.
The order was not fixed. In 2025, VT returned 22.43%, while SPY returned 17.72%. QQQ lost 32.58% in 2022, while SPY lost 18.17%.
Volatility and worst falls of each index fund
Volatility is the size of a fund's day-to-day swings, scaled up to a year. What Is Volatility? explains it. The worst fall is the largest drop from a previous high, covered in What Is a Drawdown?
Source: YX Insights
Chart 3 sets the two side by side for the same ten years. QQQ swung the most, at 22.6% a year. SPY's volatility was 17.9%, while VT's was 17.2%.
The worst falls were close together. SPY fell 33.7% from 19 February to 23 March 2020. VT fell 34.2% in the same crash. QQQ's worst came later, a fall of 35.1% from December 2021 to November 2022.
So spreading across 49 countries did not soften the deepest fall. The FTSE All-World itself fell 33.7% at its worst over the ten years, according to FTSE Russell.
How to compare index funds
Check what the index holds. The number of companies says less than the weight of the top ten.
Check the country mix. A world index still put 62.28% in US companies.
Compare over the same dates. One year can flip the order, as 2025 did.
Check the fee. SPY charges 0.0945% a year, QQQ 0.18% and VT 0.06%. Index Funds vs ETFs explains the two ways to hold one.
Check where the fund is based. A fund from abroad can be sold to individual UK investors only if the UK regulator has approved it. That approval is called recognition. No US funds have it. What Is the S&P 500? covers the London-listed versions.
The S&P 500 holds 500 large US companies, while the Nasdaq-100 holds 100 Nasdaq-listed giants with more weight in technology. The FTSE All-World spreads across 49 countries, yet US companies still made up 62.28% of it. Over the ten years to September 2026, the most concentrated index returned the most, with the biggest swings.
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Common questions about the S&P 500, FTSE All-World and Nasdaq-100
Is the FTSE All-World better than the S&P 500?
Neither is better in every period. Over the ten years to 30 September 2026, an S&P 500 fund returned 15.2% a year, against 12.3% for a world fund. In 2025, the world fund returned 22.43%, while the S&P 500 fund returned 17.72%. The world index spreads across 49 countries, while the S&P 500 holds only US companies.
Does the FTSE All-World include the S&P 500 companies?
It holds the largest of them. Nine of the FTSE All-World's ten largest holdings were also in the S&P 500's top ten on 6 October 2026. In all, it held 483 US companies, which made up 62.28% of the index on 30 September. So owning both doubles up on the largest US companies.
What is the difference between the S&P 500 and the Nasdaq-100?
The S&P 500 holds 500 large US companies from every sector. The Nasdaq-100 holds 100 large companies listed on the Nasdaq exchange and leaves out financial companies. Its ten largest holdings made up 46.86% of the index, against 39.3% for the S&P 500. A Nasdaq-100 fund returned more over ten years, with bigger swings.
Is the Nasdaq-100 riskier than the S&P 500?
Over the ten years to 30 September 2026, the Nasdaq-100 fund swung more. QQQ's volatility was 22.6% a year, against 17.9% for SPY. QQQ fell 35.1% at its worst, while SPY fell 33.7%. In 2022, QQQ lost 32.58% while SPY lost 18.17%. Over that decade, the more concentrated index swung more.
What is the difference between the S&P 500 and the FTSE 100?
The S&P 500 holds 500 large US companies, while the FTSE 100 holds the 100 largest companies on the London Stock Exchange. Their biggest holdings differ. Nvidia, a chipmaker, was the S&P 500's largest at 8.59% on 6 October 2026. HSBC, a bank, was the FTSE 100's largest at 10.19% at the end of August 2026, ahead of Shell, an oil company.
DISCLAIMER: This article is strictly educational. Any information or analysis in this note is not an offer to sell or the solicitation of an offer to buy any securities. Nothing in this note is intended to be investment advice and nor should it be relied upon to make investment decisions. Any opinions, analyses, or probabilities expressed in this note are those of the author as of the note's date of publication and are subject to change without notice.