Two thirds have no idea about the lifetime allowance is and three quarters are doing nothing to mitigate its impact, researchers discovered.
The results of the survey from pension provider Liberty Sipp come just weeks before the lifetime pension allowance is slashed by a sixth.
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John Fox, managing director of Liberty Sipp said: "The reality is that many higher earners risk sleepwalking into a tax trap, as the reduction in the lifetime allowance will see thousands of Britons hit with an eyewatering 55% charge on any pension savings over £1.25m.
"Given that there's a good chance that the lifetime allowance will be reduced even further in future, it is very worrying that so many people know so little about it, and are doing nothing to protect themselves from being caught in the widening tax net. Such ignorance is bliss only for the taxman."
Mr Fox said the most striking finding was savers' reluctance to take steps to lessen the potential impact of the lifetime allowance on their pension pot.
Some 76% said they were doing nothing to mitigate its effects.
He said: "Many people who save hard into their pensions do so blissfully unaware of what the lifetime allowance is.
"And even among those who have heard of the lifetime allowance, there is a widespread perception that it's a wealth tax that will never affect them.
"Sadly that's a dangerously complacent view.
"The reduced lifetime allowance will no longer be just a tax on the rich.
"We recently crunched some numbers and found that many people in their thirties and forties with decent, if not huge, pension pots are likely to exceed the lifetime allowance of £1.25m without even making any further contributions, triggering a huge tax charge."