Up to 100 jobs could be at risk after Simplyhealth announced it would move all its private medical insurance operations to its Bristol base.
The healthcare provider currently employs 105 people at its Letchworth site.
But Simplyhealth said it has been looking at how best to "align the business, systems and people" and cited the fact that the Letchworth base leads to "duplicate functions".
A spokesperson for Simplyhealth said it is "too early to tell at the moment" how many jobs will be lost during the process.
She said: "What we are doing is entering into a 90-day consultation with employees and look at making a decision after that. Any movement will take at least 18 months.
"We will give as much opportunity for people to relocate to Bristol as possible."
Meanwhile, Jamie Wilson, sales and marketing director at Simplyhealth, said the decision came after the healthcare business of Groupama Insurance was bought in April.
He said: "Since completing our purchase we have been looking closely at how best to align the business, systems and people with the rest of the Simplyhealth operation, while maintaining our service to customers.
"Simplyhealth has a private medical insurance operation in Bristol, and with two operations there are duplicate functions.
"We have decided to combine our two private medical insurance operations into one location, to enable us to bring together expertise and deliver a fair and consistent service to all of our private medical insurance customers."
He explained that work has already begun on constructing a new building in Bristol with "sufficient spare capacity" for the combined operation.
"In order to create a sustainable private medical insurance business for the future, Simplyhealth needs to operate in an efficient and effective way, whilst maintaining service to customers," he added.
"By combining our two operations into a single location we will realise necessary value and efficiencies."