After-Hours US Stocks: Yellen's Bond Buyback Fails to Curb Rates, Oil Prices Surge Again! Dow Plunges Over 700 Points, Walmart Crashes More Than 9%

US stock markets ended Thursday (20th) in the red across the board. Despite the US Treasury Department’s announcement of expanded bond repurchases, long-term Treasury yields continued to rise, failing to ease investor concerns. Meanwhile, the Trump administration’s threat to impose the harshest-ever economic sanctions on Iran pushed up international oil prices, sending the VIX fear index soaring.

The Dow Jones Industrial Average plunged over 700 points at closing, the S&P 500 Index fell 0.87%, and the Nasdaq Composite declined 1%. The Philadelphia Semiconductor Index narrowly closed positive, up 0.53%.

On Wednesday, the US Treasury announced it would at least double the repurchase scale of 10-year, 20-year, and 30-year government bonds over the coming months in an attempt to relieve recent bond market selling pressure. Treasury Secretary Yellen further stated on Thursday that the repurchase size might exceed the initially announced $4 billion. However, these comments did little to calm investor anxiety.

The 10-year Treasury yield rose more than 5 basis points to 4.704%, while the 30-year yield climbed to 5.248%. Earlier in the week, the 30-year yield briefly touched a nearly 20-year high.

Tensions between the US and Iran escalated, adding further pressure on US stocks. President Trump posted on Truth Social Wednesday, stating the US would launch the 'most destructive economic action in history' against Iran. Yellen echoed this on Thursday, saying the US would impose the 'strictest sanctions ever' on Iran.

October-delivery WTI crude futures rose nearly 3% to $86.83 per barrel. Brent crude futures gained over 2% to $93.78 per barrel, briefly approaching $95 — their highest level in nearly four weeks.

Meanwhile, Trump urged Congress to pass a cryptocurrency bill. Bitcoin surged past $70,000 for the first time since early June, triggering the largest short-covering rally in crypto history since records began in 2021, lifting shares of crypto-related companies like Coinbase.

Markets now await Federal Reserve Chair Powell’s speech at the Jackson Hole global central banking symposium next week for clues on the future path of interest rate policy.

Major US Indices on Thursday (20th):

Dow Jones Industrial Average: Down 703.84 points (-1.32%) at 52,759.21 Nasdaq Composite: Down 263.93 points (-1.00%) at 26,067.17 S&P 500: Down 66.82 points (-0.87%) at 7,641.16 Philadelphia Semiconductor Index: Up 61.79 points (+0.53%) at 11,800.02 NYSE FANG+ Index: Down 63.70 points (-0.35%) at 18,296.38

Key Stocks:

Tech giants within the NYSE FANG+ Index were broadly red. Meta (META-US) dipped 0.04%; Apple (AAPL-US) fell 1.75%; Alphabet (GOOGL-US) declined 1.17%; Microsoft (MSFT-US) slipped 0.47%; Amazon (AMZN-US) dropped 2.16%.

Semiconductor stocks showed mixed results. AMD (AMD-US) rose 0.65%; Broadcom (AVGO-US) gained 0.43%; NVIDIA (NVDA-US) fell 0.33%; Applied Materials (AMAT-US) edged up 0.12%; Qualcomm (QCOM-US) declined 0.72%; Micron (MU-US) surged 3.97%.

Memory stocks rallied across the board. Micron (MU-US) jumped 3.97%; Western Digital (WDC-US) rose 1.51%; SanDisk (SNDK-US) gained 2.02%; Seagate (STX-US) climbed 2.12%; SK Hynix ADR (SKHY-US) soared 4.43%.

Taiwanese ADRs mostly rose. TSMC ADR (TSM-US) gained 0.95%; ASE ADR (ASX-US) rose 2.38%; UMC ADR (UMC-US) fell 0.66%; China Telecom ADR (CHT-US) gained 0.84%.

Corporate News:

Walmart (WMT-US) plummeted over 9% to $103.84 per share, marking its worst single-day performance in over four years and dragging down the Dow. Walmart’s Q2 results missed market expectations. US same-store sales growth excluding fuel was 2.6%, below even the most pessimistic analyst forecasts and the slowest pace in over six years. Its adjusted earnings outlook for Q3 and the full year also disappointed.

Following Walmart’s earnings report, consumer stocks including Costco (COST-US), Kroger (KR-US), and Target (TGT-US) also declined.

NVIDIA (NVDA-US) fell 0.33% to $216.85 per share. On Thursday, the company denied a report from The Information, emphasizing it does not plan to ship AI chips designed for Chinese customers before year-end.

Moderna (MRNA-US), which surged about 177% on Wednesday due to positive news on its melanoma vaccine, gave back some gains on Thursday, plunging approximately 24% to $133.32 per share.

CrowdStrike (CRWD-US) dropped 5.6% to $190.34 per share. Axios reported that the company’s CTO is leaving to launch an AI security fund, dragging down other cybersecurity stocks such as Palo Alto Networks (PANW-US).

Wall Street Analysis:

Mark Malek, Chief Investment Officer at Muriel Siebert & Co., said market enthusiasm didn’t last long because the Treasury’s buyback program failed to address the root causes of rising yields.

Adam Phillips, Managing Director of Investments at EP Wealth Advisors, said bond markets are now driven by structural factors beyond the control of the Treasury or government, rendering buybacks ineffective.

Matt Maley, Chief Market Strategist at Miller Tabak, noted investors had hoped Yellen’s comments would extend Wednesday’s yield decline, but when policy signals couldn’t offset rising oil prices, selling pressure intensified.

Dennis Debusschere, Chief Market Strategist at 22V Research, stated that the 10-year Treasury yield and oil prices are 'highly correlated.' With oil above $90 and markets not pricing in potential Fed rate hikes, yields face upward pressure, creating headwinds for equities.

All figures are updated as of press time; actual trading prices may vary.