The power of Calpers, the $193bn (€158bn) California state pension fund, to revive the fortunes of badly run companies by placing them on its "focus list" has diminished as its drive for better corporate governance falters.

According to Wilshire Associates, the investment consultant to Calpers, companies on the list have returned 15.3% over the past five years, down from a peak of 54% in 1995.