---
title: "Just over half of U.S. stocks rose Monday. Meta and the chipmakers still moved the S&P 500"
url: "https://etf.net/news/just-over-half-of-u-s-stocks-rose-monday-meta-and-the-chipmakers-still-moved-the-s-p-500-2026-09-21"
published_at: "2026-09-21T21:13:23.488Z"
updated_at: "2026-09-21T21:13:23.488Z"
byline: "ETF.net Research"
---

# Just over half of U.S. stocks rose Monday. Meta and the chipmakers still moved the S&P 500

On Monday, September 21, 2026, 3,019 of 5,851 U.S. common stocks advanced; SPY gained 1.55% while equal-weight RSP gained 0.18%.

By ETF.net Research. Published Sep 21, 2026.

Meta Platforms, Intel and Advanced Micro Devices jumped with Nvidia, already 8.1% of the S&P 500 fund SPY and up 2.3% Monday. Those four holdings contributed **0.68** percentage points of the fund’s **1.55%** gain at Monday’s close. Barron's reported Monday that Meta's Muse AI agent was the trigger for the chip rally, with Intel, AMD and Arm Holdings moving together.

Chart: Arm, Intel, Meta and AMD jumped far past the S&P 500

That is not a market in which the typical stock set the pace. It is a market in which the typical stock was present.

## Half the board advanced. Cap-weight still led

Among **5,851** U.S. common stocks listed on the NYSE, Nasdaq and NYSE American, **3,019** finished higher, **2,604** finished lower, and 228 were unchanged. Just over half the board advanced. That is the opposite of Friday, when the [Nasdaq-100 fund rose 0.63% as 3,418 U.S. stocks fell](https://etf.net/news/nasdaq-100-fund-rose-0-63-as-3-418-u-s-stocks-fell-2026-09-18). It is closer to Thursday, when [3,480 stocks rose and the S&P 500 still needed chips](https://etf.net/news/after-the-fed-hike-3-480-stocks-rose-the-s-p-500-still-needed-chips-2026-09-17).

A majority of names can rise and the cap-weighted index can still be a different session. The equal-weight S&P 500 fund RSP rose **0.18%** on share price, **1.37** percentage points behind SPY. RSP went ex-dividend **$0.80** a share on Monday. A dividend is not a rally.

On the same share-price basis, the Nasdaq-100 fund QQQ, which also went ex-dividend Monday, rose **2.77%**. The Russell 2000 fund IWM rose **0.51%**, a **2.26**-percentage-point gap.

Seventeen of 20 mega-cap stocks rose. The three that did not were Berkshire Hathaway Class B, down **1.5%**, Exxon Mobil, down **3.1%**, and Johnson & Johnson, down **0.2%**. Apple, the second-largest holding in SPY, rose **0.8%**; Microsoft rose **1.6%**.

The 10 largest holdings are **38.6%** of SPY. That concentration is the mechanism. Meta is 2.2% of the fund and contributed 0.25 percentage points by itself. Intel is 0.8% of the fund and still added 0.10 percentage points. Equal-weight cannot do that: Meta is about 0.2% of RSP.

## The past month already had this shape

Monday did not invent the split.

Chart: Equal-weight has lost 3.1% over the past month; SPY has not

Joe Mazzola, head trading and derivatives strategist at Charles Schwab, noted Monday morning that last week ended with only around 30% of S&P 500 stocks above their 50-day moving average.

Small-caps have not lost 2026.

Chart: Small-caps lead 2026. Equal-weight large-caps trail

The divide is not big versus small. It is a handful of AI-adjacent names against everything else, most large caps included. Monday’s gap did not land on small-caps. It landed on holders of the equal-weight S&P 500.

Source: etf.net, https://etf.net/news/just-over-half-of-u-s-stocks-rose-monday-meta-and-the-chipmakers-still-moved-the-s-p-500-2026-09-21. Please cite the page URL.