AXA is to make 100 managers redundant from its general insurance operation, saving the company approximately £10m a year.
Many of the cuts will be compulsory, despite the offer of a voluntary redundancy package.
About 20% of the company's management layer will be axed in the cost-cutting measure.
A spokesman said: "Wherever possible, we are seeking voluntary redundancies, so we are opening up a voluntary redundancy process for managers.
"But it is quite likely there will be compulsory redundancies out of that total of 100."
All 500 managers, which includes all grades between staff and director level, were told of the cull on Tuesday (6 November).
They have until 23 November to register for a voluntary redundancy pay-off and will be told by the end of the month if they have been successful.
"We will need to look at how many people indicate a desire to go down that route and we will need to map it out to make sure the managers we need for the future are in place.
"Only then will we be able to determine the scale and number of compulsory redundancies needed."
The company would not reveal the value of the savings, but analysts estimated the figure would be more than £10m.
The spokesman said the cuts were not linked to the effects of the 11 September terrorist attacks. "We've had teams looking at ways of reducing costs and enhancing profits for some time."
He could not rule out further staff cuts, but added: "We do have project teams looking at ways of maximising income and profits and reducing the cost base of the organisation but, beyond that, it would be wrong to speculate what that might entail."
It is understood nearly 2,000 jobs were lost following AXA's acquisition of Guardian Royal Exchange in 1999.