Zinifex Ltd. (ZFX AU), the world's second-biggest zinc producer, dropped 8 cents, or 2.8 percent, to A$2.81. Credit Suisse First Boston Inc. cut its rating to ``neutral'' from ``outperform,'' citing a recent relative share price move. Zinifex had risen 12 percent since Jan. 17 as of yesterday's close, compared with a 2.3 percent gain in the S&P/ASX 200 Index.