Top Market Losers Today: PLAB, QTTB, SIDU, PLTZ, and SMCZ Lead the Decline

Font: Financial Modeling Prep  • May 28, 2026

• Photronics (NASDAQ: PLAB) experienced a significant decline following the announcement of a securities fraud investigation.
• Q32 Bio Inc. (NASDAQ: QTTB) and Sidus Space, Inc. (NASDAQ: SIDU) saw their shares drop after revealing plans for private placements and stock offerings, raising concerns about share dilution.
• Inverse exchange-traded funds (ETFs) tied to Palantir (NYSE: PLTR) and Super Micro Computer (NASDAQ: SMCI) fell sharply, indicating strong positive performance for their underlying stocks.

Today’s market saw several notable declines. The drop in value for Photronics (NASDAQ: PLAB) was particularly steep. Other companies like Q32 Bio Inc. (NASDAQ: QTTB) and Sidus Space, Inc. (NASDAQ: SIDU) also faced significant downturns, alongside inverse exchange-traded funds (ETFs) tied to Palantir (NYSE: PLTR) and Super Micro Computer (NASDAQ: SMCI).

Photronics stock fell 36.42% to close at $34.02. This decline follows the announcement that The Law Offices of Frank R. Cruz has started a securities fraud investigation into the company. The probe concerns potential violations of federal securities laws following the company's recent earnings report.

Other companies fell after announcing plans to raise money by selling stock. Q32 Bio Inc. dropped 19.77% to $10.31 after revealing a $55 million private placement. Similarly, Sidus Space, Inc. declined 14.87% to $5.18 after pricing a $100 million stock offering. Issuing new shares can dilute the value for existing investors.

The Defiance Daily Target 2X Short PLTR ETF (NYSE Arca: PLTZ) and the Defiance Daily Target 2X Short SMCI ETF (NYSE Arca: SMCZ) also fell sharply. These funds are designed to move in the opposite direction of their underlying stocks. PLTZ’s 16.34% drop and SMCZ’s 16.32% fall show that Palantir and Super Micro Computer had very strong gains.

In summary, the day's biggest losses were not random. They were tied to specific events, including a legal investigation for one company and stock offerings that dilute shareholder value for others. The ETF declines were a direct result of strong positive performance in the stocks they are designed to short.