TSMC is trading 4.17% down now at $411.75 as rising Treasury yields compress high-growth technology valuations.
- Stalled U.S.-Iran diplomacy and higher oil prices are reinforcing risk-off sentiment.
- The Philadelphia Semiconductor Index fell 3.7% on August 18, 2026; broader U.S. markets also declined, indicating sector-wide and macroeconomic pressure rather than a fresh company-specific announcement.