Folgate Partnership employees are considering launching a class action against its former owner, after the company became the latest insurer to be hit by a pensions shortfall.
There is an estimated £4m gap in its fund.
Folgate Insurance's German owner Wüstenrot & Württembergische sold the company to Towergate Underwriting Group in October 2001 for £20m.
The Folgate Partnership, created by Towergate to underwrite business supplied by a number of "hub" brokers, is now a separate legal entity.
A source said the funding gap emanated from Wüstenrot's ownership.
"All we know is that when Wüstenrot pulled out, there was not enough in the pension fund to cover its future liabilities," they said.
"This has nothing to do with Towergate or the Folgate Partnership,
"I don't think it's a legal issue, it's more a moral undertaking that the Germans have walked away from.
"People here are very disappointed, especially the people who have been here more than a few years."
Another source told Insurance Times that employees were taking legal advice on their position.
The Folgate Partnership was unable to comment by the time Insurance Times went to press.
But Wüstenrot said it was aware of the shortfall - which it set at £1m at the time of the sale - and had undertaken to repair the situation.
It is currently evaluating the total amount of funding needed.
"The group has contractually undertaken to make good any shortfall that is found to exist in Folgate's pension scheme and to bring the funding level up the minimum funding requirement," a spokeswoman said.
"The valuation is currently underway and is now being discussed with all parties."
Several other insurers and brokers have been hit by pension holes, including Royal & SunAlliance with an estimated £44m and Aon subsidiary Minet with about £32m.
The hole was revealed as the TUC blasted employers for poor contributions to stakeholder pensions.
The TUC said the pension plight was unlikely to improve, with the average contribution to an employer-sponsored stakeholder pension around £250 per year less than was necessary.