Republicans emerged with firm majorities in both chambers of Congress after the midterms, meaning Hatch's proposed legislation could gain traction next year.

With Republicans taking control of the Senate in January, Utahs Orrin Hatch is expected to become chairman of the Finance Committee, the powerful arm that oversees retirement policy in the Senate.

The difference in projecting liabilities between the assumed-return and bond-based approach can be huge.

U.S. institutional investors say their top concern is funding status, with a majority of pensions saying they intend to improve it.