Biotech giant Amgen was replaced on S & P;’s list of best investments. The Standard & Poor’s Equity Research Group moved the company off the S & P; Top 10 portfolio in favor of drug-development company Covance. S & P; picks it companies based on predicted capital gains over the next six to 12 months. All of the stocks in the S & P; Top 10 carry the firm’s top investment ranking of five stars (strong buy). Amgen’s ranking was lowered to three stars (hold) on January 27. In 2004, the S & P; Top 10 rose 19.2 percent versus a 10.9 percent gain for the S & P; 500.