(December 16, 2019, 1:28 PM EST) -- WASHINGTON, D.C. — In a Dec. 10 supplemental brief filed in the U.S. Supreme Court, retirement plan fiduciaries claim that the U.S. government failed to explain in its brief urging the high court to deny certiorari how additional factual development could help to resolve a dispute over the standard for establishing loss causation under the Employee Retirement Income Security Act (Putnam Investments LLC, et al. v. John Brotherston, et al., No. 18-926, U.S. Sup.)....