Weekly Market Review - September 19, 2026

Prepared by Sangyong’s Market Intelligence

Executive Summary

Week Character: Mixed / Indecisive

The week of September 14-18, 2026 was characterized as Mixed / Indecisive. US markets finished essentially flat with the S&P 500 at +0.40% and the Nasdaq at +1.28%. 6 of 7 Magnificent 7 stocks advanced on the week. Korean markets closed essentially flat, with KOSPI at +0.00% and KOSDAQ at +0.00%.

The 10Y Treasury yield rose 6 bps to 5.01%, with little impact on equity multiples. The Korean won weakened 2.77% against the dollar, a meaningful FX headwind for USD investors in Korean equities.

Key stat: Divergent markets — cross-asset selectivity mattered more than directional bets.

Weekly Performance Summary

U.S. Magnificent 7

Stock	Symbol	Mon Open	Fri Close	Weekly Change	Trend
Apple	AAPL	$333	$336	+0.92%	🟢
Microsoft	MSFT	$505	$494	-2.30%	🔴
Alphabet	GOOGL	$349	$350	+0.04%	🟢
Amazon	AMZN	$254	$254	+0.07%	🟢
NVIDIA	NVDA	$211	$222	+5.36%	🟢
Meta	META	$666	$666	+0.02%	🟢
Tesla	TSLA	$359	$364	+1.48%	🟢

Korean Market Leaders

Stock	Symbol	Mon Open (₩)	Fri Close (₩)	Weekly Change	Trend
Samsung Elec.	005930	₩N/A	₩260,000	N/A	🟡
SK Hynix	000660	₩N/A	₩1,849,000	N/A	🟡
Hyundai Motor	005380	₩N/A	₩366,500	N/A	🟡

Indices

Index	Mon Open	Fri Close	Weekly Change	Trend
S&P 500	7,619.98	7,650.50	+0.40%	🟢
Nasdaq	26,186.41	26,522.54	+1.28%	🟢
Dow Jones	52,421.20	51,682.64	-1.41%	🔴
KOSPI	N/A	6,894.23	N/A	🔴
KOSDAQ	N/A	827.12	N/A	🔴

Currency (KRW/USD)

Monday: ₩1,348
Friday: ₩1,386
Weekly Change: +2.77% (KRW weakened — USD stronger)
Impact: Meaningful FX drag for USD investors in Korean equities.

U.S. 10-Year Treasury Yield

Monday: 4.95%
Friday: 5.01%
Weekly Change: +6 bps
Implication: +6 bps — rising yields pressure high-multiple growth stocks; materially restrictive.

Weekly Trends and Themes

1. US Market Performance

S&P 500: +0.40% | Nasdaq: +1.28% | Dow: -1.41%

The S&P 500 was essentially flat on the week (+0.40%), with no decisive directional move — buyers and sellers in equilibrium.

Magnificent 7: 6 of 7 Mag7 stocks advanced. Best: NVIDIA (+5.36%), worst: Microsoft (-2.30%).

Takeaway: Consolidation week — no tactical change needed.

3. Currency Impact (KRW/USD)

Weekly KRW Move: +2.77% ₩1,348 → ₩1,386

The won weakened significantly (+2.77%, ₩1,348 → ₩1,386) — a meaningful drag for USD-denominated investors in Korean equities. A 2.8% currency loss partially or fully offsets any index gain.

Investor Implication: Hedge KRW exposure or reduce Korean position size to account for FX drag.

Export sector note: KRW weakness boosts revenues for Samsung, Hyundai, SK Hynix when reported in USD — watch for guidance upgrades.

4. Treasury Yields

10Y: 4.95% → 5.01% (+6 bps)

The 10Y yield drifted higher by +6 bps to 5.01% — a modest rise, not enough to drive a major equity repricing.

Market Implication: Mild headwind for high-multiple names; monitor direction next week.

5. Key Weekly Observation

Markets moved in a relatively correlated fashion this week — few compelling cross-asset divergences to exploit.

Best and Worst Performers

Best (Weekly Upside Movers):

NVIDIA: +5.36% ██████████
Tesla: +1.48% ██
Apple: +0.92% █
Amazon: +0.07%
Alphabet: +0.04%

Worst (Weekly Declines):

Alphabet: +0.04%
Meta: +0.02%
Microsoft: -2.30% ████

Commentary:

NVIDIA was the standout winner at +5.36% — a weekly gain of this size reflects either strong earnings catalysts, analyst upgrades, or a short-covering squeeze. Verify whether the move is fundamental or technical before chasing.

Microsoft underperformed at -2.30% — watch whether the weakness continues into next week or reverses.

6 of 7 stocks advanced. Breadth is healthy — more gainers than losers.

Weekly Review Compiled: September 19, 2026 at 12:10 PM Analysis Period: September 14 - 18, 2026 Data Sources: Daily market reports, Naver Finance, Yahoo Finance, FRED