S&P 500: ten companies weigh 41% of the index as of October 6, 2026, according to Citadel Securities data

A 41% concentration according to Citadel Securities

On October 11, 2026, Le Journal du Coin published an article based on data from Citadel Securities, visualized by The Kobeissi Letter. According to these figures, 41 cents of every dollar invested in the S&P 500 goes to the ten largest market capitalizations in the index. The outlet notes that Citadel Securities rounds this figure to 41 for the October 6, 2026 reading. The index nonetheless includes five hundred companies.

According to market data from Yahoo Finance, the S&P 500 stood at 7,811.54 points, up 0.59% on the session, based on a data point from October 9, 2026 at 11:29 p.m. Paris time.

The ranking in detail

According to The Kobeissi Letter's chart, Nvidia ranks first with 8 cents. Next come Apple with 7 cents, Microsoft and Alphabet with 6 cents each, then Amazon with 4 cents. Broadcom, Meta, Tesla, Micron and AMD together account for 10 cents.

Le Journal du Coin continues its reading: the companies ranked eleventh through twentieth receive 10 cents. Twenty companies therefore absorb 51 cents, more than half of the dollar. The next eighty receive 26. At the bottom of the ranking, the 402 smallest stocks share 23 cents, less than the top four combined.

The weight of chipmakers

Le Journal du Coin offers another way of reading the data: Nvidia, Broadcom, Micron and AMD, four chipmakers, together weigh 14 cents. The outlet concludes that buying the US market today amounts to taking a significant position in artificial intelligence. This is its own interpretation, not a finding of Citadel Securities.

A comparison with the past

Le Journal du Coin cites series from Goldman Sachs Asset Management: the ten largest stocks represented about 22% of the index in 1973, then 27% at the peak of the internet bubble in 2000. This summer, readings ranged between 36.5% and 41% depending on the calculation methods.

The outlet also cites the website Benzinga, which points to a record: Nvidia, Apple and Microsoft together weigh 21% of the index. In the mid-1980s, the trio of IBM, AT&T and Exxon peaked at 13.4%.

A self-reinforcing mechanism

Le Journal du Coin explains that the index weights each company according to its market value. The more a stock rises, the greater its weight grows, and the more funds tracking the index must buy it. According to the outlet, this mechanism feeds on itself while Wall Street keeps setting records.

Analysis: what these figures suggest

This analysis relies solely on the elements reported by Le Journal du Coin. The outlet notes that the two best-known concentration peaks, 1973 and 2000, were followed by long bear markets. It immediately qualifies this: two examples do not make a rule, and a concentrated index is not doomed to fall. Its trajectory simply depends on the health of a handful of companies.

According to the outlet, if Nvidia weakens, an ETF tracking the index feels the effects, whatever the performance of the 402 smallest holdings. It mentions an equal-weighted version, in which each company has the same weight: it corrects this bias, but at the cost of far less exposure to the tech giants.

Le Journal du Coin finally draws a parallel with cryptocurrencies, where a so-called diversified portfolio often remains a bet on bitcoin, with the rest of the market following its trajectory. It invites readers to examine an index's composition before believing it to be a risk spreader.