The TUC is calling for an end to “secrecy” in the City about how pension fund managers vote on issues such as executive pay.
The trade union body wants more openness and said it is to survey managers and pass the findings to pension fund trustees.
In last year’s TUC survey, nine out of 10 managers would not say how they voted.
TUC general secretary Brendan Barber said it had begun to “lift the veil” on how managers run billions of pounds on behalf of pensions savers.
The aim of the survey was to find out how fund managers were exercising their rights to vote in companies they had invested in, and how they addressed the way the firms were governed.
Barber said: “Only just over half of fund managers responded to [last year’s] survey voluntarily, an improvement but not enough, and almost all the rest say they have no intention of publishing their voting decisions.
“A number of major investors are already disclosing but others have made it clear that they will only do so if there is a level playing field on which everybody has to be transparent.
“The government should stick to its ambition of ending secrecy in the City by requiring all fund managers to disclose how they vote at company [annual general meetings].”