CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM, New York City Employees Retirement System, New York City Police Pension Fund, Police Officers Variable Supplements Fund, Police Supervisor Officers Variable Supplements Fund, New York City Fire Department Pension Fund, Fire Fighters Variable Supplements Fund, Fire Officers Variable Supplements Fund, Board of Education Retirement System of the City of New York, Teachers Retirement System of the City of New York, New York City Teachers Variable Annuity Program, and Indiana Electrical Workers Pension Trust Fund IBEW, Plaintiffs Below, Appellants, v. Aida M. ALVAREZ, James I. Cash, Jr., Roger C. Corbett, Douglas N. Daft, Michael T. Duke, Gregory B. Penner, Steven S. Reinemund, Jim C. Walton, S. Robson Walton, Linda S. Wolf, H. Lee Scott, Jr., Christopher J. Williams, James W. Breyer, M. Michele Burns, David D. Glass, Roland A. Hernandez, John D. Opie, J. Paul Reason, Arne M. Sorenson, Jose H. Villarreal, Jose Luis Rodriguezmacedo Rivera, Eduardo Castro-Wright, Thomas A. Hyde, Thomas A. Mars, John B. Menzer, Eduardo F. Solorzano Morales, and Lee Stucky, Defendants Below, Appellees, Wal-Mart Stores, Inc., Nominal Defendant Below, Appellee