The Central Bank's investigation and inquiry into regulatory breaches at the defunct Irish Nationwide Building Society (INBS) cost a total of €24m or an average of €1.6m over 15 years.

The investigation and inquiry was the largest and most complex ever carried out by the financial regulator, which said the costs reflect the external support and advisors required to pursue the evidence through to a full inquiry.

The Central Bank expects that additional costs will be incurred over the coming months with the application to the High Court for confirmation of the inquiry decision.

The initial investigation from 2010 to 2015 is estimated to have cost €4.97m while the resulting 10-year inquiry cost a further €16.58m. Litigation costs between 2015 and 2018 came to €2.72m, and external costs came to a total of more than €24.26m.

Separate to those external costs, the Central Bank incurred previously reported operational costs of €7.8m to ensure the inquiries were operationally fit for purpose.

The costs related to leasing and equipping premises for public and private hearings, acquiring technology to efficiently progress hearings, and professional fees associated with the design, build and implementation of technology and audio visual infrastructure.

In its final report, published on Wednesday, the Central Bank disqualified INBS's former finance director Stan Purcell from managing a regulated financial firm for four years and fined him €130,000 for his role in the breaches.

Central Bank governor Gabriel Makhlouf said the decision "concludes an important enforcement action taken by the Central Bank in the public interest.

"It is critical to public trust and confidence in financial services that there is a credible threat of such enforcement for firms and individuals who break the rules put in place to protect consumers and the stability of the financial system," he continued.

“The sanctions imposed by the Inquiry and through the settlements with INBS and the other individuals highlight the important position of senior role holders and board members in the financial industry.

"The Inquiry Decision shows the very serious impact failures at board level can have and provides valuable lessons to senior role holders in the financial services industry. It is essential that such key role holders take responsibility for and drive effective risk management and strong governance."

Regarding the cost of the investigation and inquiry, Makhlouf said it reflected its length and complexity, "including the extensive work to unearth the facts through a large volume of documentation and witness evidence, and the need to defend the statutory framework in the face of court challenges by persons under Inquiry. "

The initial investigation examined INBS's commercial lending in Ireland, Belfast and London over four years, and engaged external consultants and professional advisors.

The Central Bank gathered approximately 350,00 documents and produced a 3,500-page investigation report and two supplemental investigation reports addressing additional evidence, supported by 111,000 documents.

The subsequent inquiry from 2015 to 2025 involved the appointment of three independent individuals to conduct it, who were supported by legal advisers and external data management and technology support.

The substantive hearing ran for 105 days between 2017 and 2021, with oral evidence from 33 witnesses, and the final inquiry decision runs to 1,400 pages.

"The lessons learnt have led to changes to the legislative framework, which have introduced efficiencies and further safeguards, including the Individual Accountability Framework," said Makhlouf.

"The Central Bank will continue to use the full extent of its powers to enforce the rules put in place to protect consumers, the integrity of our markets and the stability of the financial system that serves our society.”

INBS was bailed out with a €5.4bn government rescue package in 2010 and was subsequently nationalised. The lender reported a loss of €2.5bn in 2009 after writing off €2.8bn in loans, equivalent to nearly a quarter of its loan book.

In addition to Purcell, the inquiry focused on four other former executives: managing director Michael Fingleton, chairman Michael Walsh, head of UK lending Gary McCollum, and head of commercial lending Tom McMenamin.

Walsh was disqualified for three years and fined €20,000, McMenamin was disqualified for 18 years and fined €23,000, and McCollum was disqualified for 15 years and fined €200,000.

The Central Bank identified more than 40 regulatory breaches during its inquiry.

(Pic: Artur Widak/NurPhoto via Getty Images)