Employees of Pfizer Inc. have filed suit against the company, alleging the world's largest drug maker failed to properly manage its retirement plans and caused losses totaling hundreds of millions over the past decade in one of the hubs of the pharmaceutical industry. The suit, filed Wednesday in federal court in Puerto Rico, alleges Pfizer allowed employees to amass such high concentrations of company stock that workers were extremely vulnerable to market fluctuations and says the plans could not be considered prudently managed as required by the U.S. law. The suit also claims Pfizer withheld information that damaged workers as shareholders.