Aegon has hit back at claims their due diligence processes prevent them from transferring pensions swiftly to PensionsBee.
In an open letter to Aegon's chief executive Adrian Grace, dated 27 January, PensionBee's founder Romi Savova accused the firm of causing detriment to clients.
She wrote: "Aegon's arduous transfer approach for our mutual customers is out of line with that of its peers, who enable customers to switch their pensions quickly and safely to their chosen provider.
"The average transfer out of Aegon for completed transfers now takes circa 54 days - although the true scale of detriment remains unknown, since many people have been unable to overcome the barriers placed in front of them by Aegon in their attempts to switch or have simply given up.
"This is all extremely puzzling as prior to 8 June 2017, Aegon readily used electronic means to transfer the policies of over 300 customers to the PensionBee Personal Pension."
She said customers wishing to transfer out of Aegon to PensionBee had been asked to fill in multiple discharge forms, and engage in telephone calls and repetitive requests for information that had already been provided.
In contrast to Aegon other providers, including Aviva, Legal & General, Prudential, Scottish Widows and Standard Life, typically transferred electronically in 12 days or less, according to Ms Savova.
PensionBee said Aegon had already paid out to several clients who lost investment money waiting for their transfers when they demanded it, as well as sending one client a £100 apology cheque for the delays.
The latest client gripe, which involved an invoice for 12 hours of lost time filling in forms and sending emails, was for £432.
A letter sent by Aegon's risk officer stated there were a "number of points" made by PensionsBee "we would dispute".
He added the suggestions made by PensionsBee as to why delays were happening did not have any "bearing on our approach to pension transfers".
In a statement to FTAdviser today (29 January) a spokesman for Aegon said: "Aegon is very much at the forefront of using digital technology to support advisers and connects electronically whenever possible within the bounds of technology and our regulatory responsibilities.
"Having invested heavily in systems to ensure that pensions transfer safely and efficiently, either to another provider or to us, we use a digital transfer service whenever possible.
"Where this isn't possible we operate appropriate procedures to meet our regulatory and legal responsibilities. Transfer requests from PensionBee are treated in line with Aegon's due diligence processes, which are in place to meet our legal and regulatory obligations.
"Aegon have reviewed our overall approach in respect of PensionBee and is comfortable that our approach is appropriate."
This is the latest instalment of an ongoing spat between Aegon and PensionsBee.
The problem centres on Aegon allegedly refusing to carry out electronic pension transfers to fintech provider PensionBee via Origo Options transfers.