As per the official statement, the regulatory failings impacted 15,910 tracker mortgage customer accounts between August 2004 and June 2022.
BoI has admitted to 81 separate regulatory breaches, the central bank said.
Specifically, the key findings show that BoI’s contractual documents for mortgages were unclear and ambiguous in terms of customers’ right to a tracker rate after a fixed rate period.
For nine years, the Irish bank interpreted these documents in its favour and its customers were denied a tracker rate.
The lender did not warn customers about the consequences of the decision to move to a fixed rate or if they broke early from a fixed rate period.
The investigation also found that BoI customer complaints handling practices implemented by the bank were unfair and deficiencies in its systems and controls resulted in operational errors.
Furthermore, the bank wrongfully excluded customers from the protections of the central bank’s tracker mortgage examination (TME).
Responding to the fine, Bank of Ireland Group interim chief executive Gavin Kelly said: “Today’s statement from the Central Bank of Ireland is extremely critical of Bank of Ireland. We understand – and fully accept – why this is. What took place in relation to tracker mortgages was wrong. It should never have happened. We are very sorry that it did.
“We unreservedly apologise to all customers harmed by the tracker mortgage issue. We have learned the hard lessons, and have taken steps to ensure we are a more customer-focused bank today.”
Earlier this week, the state’s shareholding in BoI reduced to zero, making it the first bank to return to private ownership. It was bailed out during the financial crisis.