Nasdaq-100 fund rose 0.63% as 3,418 U.S. stocks fell
Friday, September 18, 2026: 2,167 of 5,845 U.S. common stocks advanced; Nasdaq-100 fund QQQ gained 0.63% while equal-weight S&P 500 fund RSP fell 0.48%.
After the Fed hike, 3,480 stocks rose on Thursday. On Friday the majority went the other way, and the Nasdaq-100 fund kept climbing anyway.
Among 5,845 U.S. common stocks listed on the NYSE, Nasdaq and NYSE American, 2,167 advanced and 3,418 declined. That is 37% rising. The Nasdaq-100 fund QQQ still gained 0.63%. The S&P 500 fund SPY slipped 0.12%. The equal-weight S&P 500 fund RSP fell 0.48%, giving back Thursday's 0.49% rise, and the Russell 2000 small-cap fund IWM dropped 0.49%.
Only QQQ finished higher among the four funds
- +0.6%
- −0.1%
- −0.5%
- −0.5%
Thursday's broad session lasted one day.
Equal-weight S&P 500 lagged by 0.36 percentage points
RSP trailed SPY by 0.36 percentage points on Friday. That is not a rounding difference. The cap-weighted fund holds 39% in technology; the equal-weight fund holds 17%. When a handful of semiconductor stocks rise and the rest of the board does not, those two portfolios are different markets.
On September 11, equal-weight S&P 500 was down 2.8% in a month as the cap-weighted fund fell 1.1%. As of Friday those trailing one-month figures are down 4.4% for RSP and 0.71% for SPY, a gap of 3.7 percentage points. IWM is down 5.6% over the same month.
StreetStats, as of the close on Thursday, September 17, put 31% of S&P 500 members above their 50-day average and said participation remains narrow beneath the index.
Eight of 20 mega-cap stocks rose. Nvidia gained 1.3%, Broadcom 3.0%, Amazon 1.0% and Alphabet 0.6%. Twelve fell, including Microsoft (-0.8%), Apple (-0.3%), Meta Platforms (-2.4%) and Netflix (-4.7%). Netflix's drop followed a Wells Fargo downgrade to underweight and a price-target cut to $57 from $80, reported Friday.
Cap-weighted Nasdaq-100 and semiconductors rose. Equal-weight S&P 500 and small-caps gave back Thursday's gains. The utilities sector fund XLU closed at $41.09, a cent above its 52-week low.
Micron, Sandisk, Nvidia and AMD added 0.53 percentage points
QQQ did not rise because the Nasdaq-100's typical stock rose. Micron, now the fund's fourth-largest holding at 4.9%, gained 3.9% and added 0.19 percentage points. Sandisk jumped 11.0% and added 0.12. Nvidia added 0.11. Advanced Micro Devices added 0.11. Those four positions contributed 0.53 percentage points to a fund that gained 0.63%.
Meta subtracted 0.08 percentage points, Netflix 0.07, Qualcomm 0.05 and Microsoft 0.05. Inside the same index, memory and GPU names more than offset the software and streaming names that fell.
The semiconductor fund SMH rose 2.21%, extending Thursday's 2.76% gain. The S&P 500 technology sector fund XLK added 0.82%. Nvidia, Broadcom and Micron together added 0.25 percentage points to SPY.
Wednesday's session had the same shape: 3,494 stocks fell, and the Nasdaq-100 fund still edged higher after the Federal Reserve's first rate increase since 2023. Friday restored that split.
The CBOE Volatility Index, priced off S&P 500 options, fell 4.1% to 14.81 after the close, as of 4:14 p.m. Eastern. That is a reading on the cap-weighted S&P 500, where SPY barely moved, not on the 3,418 stocks that declined.
Frequently asked
How can the Nasdaq-100 fund rise when most stocks fell?
A few large chip positions, Micron, Sandisk, Nvidia and AMD, contributed 0.53 percentage points of the fund's 0.63% gain, more than offsetting declines in software and streaming names.
Why did equal-weight trail the S&P 500 fund?
The cap-weighted fund holds 39% in technology versus 17% for the equal-weight fund, so a semiconductor rally lifts one and not the other.
How wide is the gap over a month?
The equal-weight S&P 500 fund is down 4.4% over the trailing month while the cap-weighted fund is down 0.71%, and small-caps are down 5.6%.
Does the low volatility reading mean the market was calm?
The VIX is priced off S&P 500 options, so it reflects the cap-weighted index that barely moved, not the 3,418 stocks that declined.