Weekly Market Review - August 15, 2026

Prepared by Sangyong’s Market Intelligence

Executive Summary

Week Character: Mixed / Indecisive

The week of August 10-14, 2026 was characterized as Mixed / Indecisive. US markets finished essentially flat with the S&P 500 at +0.42% and the Nasdaq at +0.47%. 2 of 7 Magnificent 7 stocks advanced on the week. Korean markets closed dramatically higher, with KOSPI at +10.77% and KOSDAQ at +1.19%.

The 10Y Treasury yield fell 1 bps to 4.68%, with little impact on equity multiples. The Korean won strengthened 0.07% against the dollar — a negligible FX effect.

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

Weekly Performance Summary

U.S. Magnificent 7

Korean Market Leaders

Indices

Currency (KRW/USD)

• Monday: ₩1,418
• Friday: ₩1,417
• Weekly Change: -0.07% (KRW strengthened — USD weaker)
• Impact: Negligible FX impact this week.

U.S. 10-Year Treasury Yield

• Monday: 4.69%
• Friday: 4.68%
• Weekly Change: -1 bps
• Implication: Stable yields — no rate-driven equity repricing this week.

Weekly Trends and Themes

1. US Market Performance

S&P 500: +0.42% | Nasdaq: +0.47% | Dow: -0.45%

The S&P 500 was essentially flat on the week (+0.42%), with no decisive directional move — buyers and sellers in equilibrium.

Magnificent 7: 2 of 7 Mag7 stocks advanced. Best: NVIDIA (+3.50%), worst: Amazon (-5.55%).

Takeaway: Consolidation week — no tactical change needed.

2. Korean Market Performance

KOSPI: +10.77% | KOSDAQ: +1.19% (weekly)

KOSPI surged +10.77% — a strong weekly gain suggesting genuine institutional re-entry, not just short-covering.

KOSDAQ modestly higher (+1.19%), underperforming KOSPI — investors preferring large-cap stability.

Among Korean blue chips: Samsung led (+19.35%), Hyundai lagged (+11.03%).

Takeaway: Strong week for Korean markets — partial position add appropriate.

3. Currency Impact (KRW/USD)

Weekly KRW Move: -0.07% ₩1,418 → ₩1,417

The won was virtually unchanged (-0.07%) — no currency-driven distortion to Korean equity returns this week.

Investor Implication: Neutral for Korean stock investors denominated in USD.

Export sector note: Stable KRW — no meaningful FX-driven earnings revision expected.

4. Treasury Yields

10Y: 4.69% → 4.68% (-1 bps)

The 10Y Treasury yield held steady at ~4.68% (-1 bps for the week) — no yield-driven repricing of equities.

Market Implication: Stable rates support growth stock multiples.

5. Key Weekly Observation

• Korea outperformed the US by 10.3pp this week — unusual divergence; watch for foreign net buying data to confirm institutional re-entry.
• Wide Mag7 dispersion this week (9.1pp between best and worst) — stock-pickers’ market; index-level moves understate individual name volatility.

Best and Worst Performers

Best (Weekly Upside Movers):

• Samsung: +19.35% ████████████████████
• SK Hynix: +15.85% ████████████████████
• Hyundai: +11.03% ████████████████████
• NVIDIA: +3.50% ██████
• Tesla: +3.44% ██████

Worst (Weekly Declines):

• Microsoft: -2.11% ████
• Alphabet: -3.25% ██████
• Amazon: -5.55% ███████████

Commentary:

Samsung was the standout winner at +19.35% — 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.

Amazon was the clear laggard at -5.55% — a decline of this magnitude warrants a fundamental review. Check whether this reflects a company-specific negative (guidance cut, regulatory headwind) or macro pressure.

5 of 10 stocks advanced. Negative breadth — more stocks declining than advancing.

Weekly Review Compiled: August 15, 2026 at 12:10 PM Analysis Period: August 10 - 14, 2026 Data Sources: Daily market reports, Naver Finance, Yahoo Finance, FRED