A group of pension savers are pursuing complaints about Equitable through the PIA Ombudsman, the body that investigates individual complaints against life offices. Some may take the issue to the courts.
They are complaining about pension policies which included a guaranteed minimum annuity rate, which promised a minimum rate of income from their savings on maturity.
Annuity rates determine the level of income a saver will get from their fund on retirement. The annuity rate - and the income - depends on the yield on government gilts, which fluctuate as markets rise and fall. By guaranteeing a minimum rate, life offices sought to reassure savers that their income would be protected.
But the policyholders say Equitable's policies are failing to do that, at a time when the markets are offering one of the worst annuity rates available.
Some Equitable policies, issued more than 10 years ago, offered to guarantee annuity incomes at more than 10 per cent of the fund, so pounds 100,000 would pay out over pounds 10,000 a year, compared with around pounds 7,000 on the open market.
But Equitable has told savers they cannot get a guaranteed rate for their entire pension saving. If they want the guaranteed rate, they will forego part of their terminal bonus, a sizeable chunk of their fund .
Equitable says it has always made this clear in its contract. Nigel Webb, spokesman for the society, said the guarantees were always a choice between a guarantee for part of the fund (consisting of premiums plus annual bonuses) or a market rate for all of it. But policyholders say they were never made properly aware of this.
The recent turmoil in financial markets has caused a flight of money from shares to gilts, forcing gilt prices up, causing yields to fall to an all-time low and annuity rates to plunge.
The annuity specialists, Annuity Bureau, says a typical saver retiring with pounds 100,000 can now get just pounds 7,040 a year, compared to pounds 13,280 in 1990.