O2Micro

(OIIM) - Get Report

was down 20.3% in midmorning to a 52-week low of $6.88 after it warned that fourth-quarter earnings per share would be 5 cents, 1 cent below the

First Call/Thomson Financial

estimate. The integrated circuitmaker said sales would be about flat with the third quarter's.

O2Micro, which went public in August, is down from a high $28.63 on Sept. 1.