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September 18, 2026 · week in review

Goldman Sachs Drags the Dow While Alphabet Lifts the Nasdaq in a Split Week

The S&P 500 finished almost exactly where it started as a Goldman Sachs slide sank the Dow and an Alphabet surge carried the Nasdaq 100 the other way.

The S&P 500 closed the week at 7,650.50, down 6.48 points, or 0.08%, from September 11 to September 18. That headline is close to a rounding error, but the week underneath it was not calm. Only 137 of the index's 503 members rose, and the concentration reading hit 257%, meaning the gross push and pull from the top handful of stocks dwarfed the tiny net change. An equal-weighted version of the index fell 1.31% over the same stretch, a wide gap from the 0.08% headline that shows how much the large-cap winners were doing to hide broader softness.

The S&P 500 through the session

Broadcom was the single heaviest drag, subtracting 8.87 points on a 4.06% decline, followed by Bank of America at -4.00 points on a 7.94% drop, Amazon at -3.78 points, Goldman Sachs at -3.15 points, and Netflix at -2.91 points. On the other side, Nvidia added 10.20 points on a 1.82% gain and AMD added 8.00 points on an 8.46% jump. Alphabet's two share classes, GOOGL and GOOG, together added 13.22 points, with Apple contributing another 6.54 points.

S&P 500 attribution map, cell size = points contributed

The Dow

The Dow told a rougher story, closing at 51,683.00, down 890.29 points, or 1.69%, with only 9 of its 30 members higher. Concentration ran at 76%. Goldman Sachs was the standout decliner, subtracting 518.16 points on an 8.47% drop, with IBM off 81.67 points, American Express off 78.04 points, Boeing off 72.81 points, and Salesforce off 58.25 points. The equal-weighted Dow fell 1.17%, a smaller gap to the headline than the S&P showed, which fits a blue-chip index where the damage was broad rather than hidden behind a few winners.

The Dow through the session

Alphabet was the Dow's best performer even as the index fell, adding 65.62 points on a 3.26% gain, followed by Amgen at 49.33 points, Johnson & Johnson at 26.21 points, Honeywell at 24.37 points, and Nvidia at 23.66 points. Those five gainers were nowhere near enough to offset the Goldman-led slide.

Dow attribution map, cell size = points contributed

The Nasdaq 100

The Nasdaq 100 diverged from both blue-chip gauges, closing at 29,644.17, up 275.73 points, or 0.94%, even though only 37 of its 101 members advanced. The payload flags this as a divergence week, and the concentration figure of 167% backs that up. Alphabet's two classes did the heaviest lifting here too: GOOGL added 221.02 points and GOOG added 185.65 points, which together came to 406.67 points, by far the largest source of the week's gain. Microsoft added 54.78 points despite falling 0.37% on the week, a reminder that Nasdaq 100 weighting can push a stock's dollar contribution in a different direction than its own return. Palo Alto Networks added 35.48 points on a 9.96% gain and CrowdStrike added 34.86 points on a 14.95% gain.

The Nasdaq 100 through the session

Working against that was Broadcom, down 104.48 points on a 4.06% decline, Space Exploration Technologies down 79.35 points despite a positive 0.99% return, Nvidia down 40.10 points, Tesla down 28.82 points, and ASML down 27.54 points. The equal-weighted Nasdaq 100 fell 0.28%, the smallest equal-weight decline of the three indexes, which lines up with a market where losses were shallower and more scattered than the Dow's.

Nasdaq 100 attribution map, cell size = points contributed

The sectors

Across the eleven sector groups, the week split roughly two against nine. Only Health Care and Technology finished positive, while every other group, from Consumer Staples to Utilities, ended lower. The spread ran from Health Care's 1.83% gain to Utilities' 3.07% loss, a wide range for a week where the S&P 500 itself barely moved.

The 11 sectors by move, top contributor named

Health Care led, up 1.83%, with Eli Lilly the top named driver, adding 0.80 points on a 3.33% gain. Technology followed at 1.03%, powered in the payload's driver slot by AMD's 8.46% move, which added 0.82 points to that sector's tally.

Health Care: what moved it

Utilities sat at the other end, down 3.07%, the weakest sector of the week. Constellation Energy was the sector's named driver, falling 10.55% and subtracting 0.32 points. Financials were close behind at -2.39%, with Bank of America as its top driver, down 7.94% and subtracting 0.25 points, and Real Estate rounded out the bottom three at -2.07%.

Utilities: what moved it

The payload does not carry a percentile reading for any of this week's index moves, so none of these figures can be sized against the past year's distribution of weekly moves. What is clear from the raw numbers alone is that the S&P 500's near-flat close concealed a week of real divergence beneath the surface, with the Dow's Goldman Sachs-led slide and the Nasdaq 100's Alphabet-led gain pulling in opposite directions.

The numbers

From Babylon Burns

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Amgen's Slide Drags the Dow While the S&P an
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Compiled by the WMTMT attribution engine from the session's official data · built by the founders of Babylon Burns