The stock fell $3.05, or 7.2 percent to $39.46 Wednesday and hit $37.15 earlier in the session, its lowest price since February 2001.

Late Tuesday, the company said hefty acquisition and integration charges dragged it to a fourth-quarter loss.

The company is spending more to manufacture newer products and is still dealing with costs for integrating Ocular Sciences, which it bought in 2005. High costs prompted Moody's Investors Service to downgrade Cooper's credit outlook to "Negative" from "Stable" in October.

The company also gave an adjusted earnings per share outlook for 2008 short of Wall Street expectations.

"Cooper threw ourselves, and it appears most investors as well, a curve ball with its fiscal 2008 guidance," said Jefferies & Co. analyst Peter J. Bye in a note to clients. "The net result of this news will erase the potential for a short-lived rally in the shares." He reaffirmed a "Hold" rating on the shares and cut his price target to $41 from $46.

Goldman Sachs analyst Lawrence Keusch lowered his rating to "Neutral" from "Buy," cut his price target to $37 from $58 and removed the stock from Goldman's "Americas Buy List," a group of recommended stocks, citing limited potential for earnings growth in the near-term. The company's outlook is likely to raise concern about future profits, even with new products, he said.

Also, operating margin expansion could be more challenging to achieve if the company increases marketing spending. Its competitors include Johnson & Johnson and Bausch & Lomb Inc., which was bought by private equity firm Warburg Pincus in October.