Coherent fell about 4.5% in the preceding session and rebounded 3.5% on September 29, without recovering that loss. Its $292.21 close remained about 9.1% below $321.52 on September 21. The returns have different starting values and cannot simply be subtracted. In price terms, the level from a week earlier was still above it.
Semiconductor ETF SMH gained about 1.1% that day, while NVIDIA lost 0.7% and AMD was almost flat. The ETF and these company market closes did not move together; the ETF’s market-price change is a separate measure from its NAV change and total return. Coherent’s rebound could reflect company factors, industry expectations, or short-term repair. Without fresh orders, it does not establish accelerating optical demand, just as a price below last week’s does not establish worsening operations. Some of the decline was recovered; earlier damage remained.
Historical backfill prepared on October 4, 2026. The observation cutoff is the article date, with US market data through the 2026-09-29 New York close. Sources: Coherent, SMH, NVIDIA, AMD. Daily returns use September 28 closes; the prior session uses September 25. The cumulative drawdown uses September 21 and 29 endpoints. SMH is a semiconductor ETF; one company is not treated as the entire optical industry. COHR, NVDA and AMD are analysis subjects only, not KSINQ recommendations to buy, sell or hold them. Personal research and opinion for information only; not investment advice.