Idenix Pharmaceuticals was the biggest stock loser across the NYSE and Nasdaq today, plunging 19.78% to close the day at $3.69.

Idenix Pharmaceutic - Stock Plunges

The company’s “shares sank after the U.S. Patent and Trademark Office determined a competitor was the first to request a patent for a hepatitis therapy.”

Shares of PGT, Inc. stock dropped 13.95%, making it the second biggest loser. The firm announced a “filing of registration statement for possible sale of shares by a major stakeholder (JLL Partners Fund IV).”