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Portrait of Guy Mrejen

Diag. IT · Independent consultant

Guy Mrejen

Senior consultant IT audit, risk and internal control · Banking & Insurance

As an independent senior consultant, I work on IT audit, risk management and internal control engagements for demanding large organisations. More than 25 years of experience at HSBC, BNP Paribas, KPMG and Deloitte.

CISAISO 27001 FoundationSix Sigma Black BeltITIL v3Paris · France
● Available for freelance engagements
ReferencesBNP ParibasHSBCKPMG CanadaDeloitteGroupamaArvalSMACL Assurances
25+years in IT audit, risk and internal control
17years at HSBC, from audit to operations management
4professional certifications
3working languages

Career

From Deloitte to Diag. IT

A career built at the heart of major players in banking, insurance and audit.

  1. Since 2019

    Diag. IT · Founder and senior consultant

    Freelance · IT audit and internal control (RCSA, GDPR, security), control plans, risk governance, reporting and documentation of critical processes.

  2. 2023 – 2026

    BNP Paribas, BP2i · Internal control

    • Led internal control and risk assessment (RCSA) across strategic business areas: Finance, Fraud, Procurement, Business continuity
    • Review of GDPR compliance plans
  3. 2022

    KPMG Canada · Senior Manager, Audit and Quality Assurance

    • Verification of audit exit criteria for the Desjardins Security Office (Montreal)
    • Quality assurance of review work, analyses and quantified summaries
  4. 2021

    SMACL Assurances · Head of IT Control

    • Design and implementation of an IT control plan (operations, projects)
    • Coordination of internal and external audits, quarterly risk reporting
    • Redesign of user access management processes
  5. 2019 – 2020

    Arval, BNP Paribas Group · IT internal control

    • 2019 control analysis: 170 corrective action plans, including 60 quick wins (security, operations, governance)
    • 2020 control plan: 402 control points across IT operations and development
    • Proposals to redesign BNP Paribas control plans (redundancies, effectiveness)
  6. 2019

    Groupama · IT security management

    • Preparation of responses to auditors cut from 6 weeks to 48 hours
    • IT security standards framework
    • Security incident, vulnerability and system hardening management processes
  7. 2001 – 2018 · 17 years

    HSBC

    Paris · Europe

  8. 2008 – 2018

    Project Manager, COO Office HSBC France and Europe

    • Monitoring of regulatory projects and data quality programme (BCBS 239)
    • Assessments of major projects and organisations with budgets from €1M to €100M
    • Process optimisation: statements turned around in 48 hours instead of 2 weeks, from 20 to 5 FTEs
  9. Head of IT Project Quality Assurance, HSBC France

    • Review of the schedules, governance and risks of 50 major projects a year
    • Monitoring of business continuity plans (hundred-year flood, pandemic)
  10. 2004 – 2008

    Manager, Strategy and Organisation Department

    • Roll-out of the Six Sigma methodology
    • Study and launch of a direct banking offer, strategic plan and KPIs
  11. 2001 – 2004

    Head of IT Audit

    • Recruited, trained and managed a team of 10 specialist auditors
    • Audit engagements on IT operations (data centre, systems, networks) and major projects
    • Negotiation of the IT outsourcing contract of a banking subsidiary (100 staff)
  12. 1997 – 2001

    CNH Industrial (Fiat) · Internal Auditor Europe · Paris

    • International IT audits (Europe, United States)
    • Coordination of Euro changeover projects
    • Audit of data centres and offshore centres
  13. 1995 – 1997

    Deloitte Touche Tohmatsu · IT Auditor · Paris

    • Information systems assessments as part of statutory audit mandates and IT audit engagements
    • Process controls at high-security printing plants
    • Clients: La Française des Jeux, Air France, Lafarge

Results

Results measured on engagements

A few concrete results achieved for my clients.

Groupama · IT security48 h instead of 6 weeks

to prepare responses to auditors, thanks to an IT security standards framework and formalised key processes.

Arval · BNP Paribas · IT internal control402 control points

managed across IT Operations and Development, and 170 corrective action plans, including 60 quick wins.

HSBC · COO Office20 → 5 FTE

on an optimised process, with statement turnaround cut from 2 weeks to 48 hours.

Expertise

A proven method across four fields

The rigour of a certified auditor, combined with hands-on knowledge of banking and insurance businesses.

Understated office space with a glass-walled meeting room
01 · Control

IT control plans

Design and management of control plans covering operations, projects and security.

  • IT internal control and RCSA
  • Annual control plans and analysis of results
  • Management of corrective action plans
02 · Compliance

GDPR and security frameworks

Regulatory compliance and formalisation of security frameworks.

  • Review of GDPR compliance plans
  • IT security standards frameworks
  • Incident, vulnerability and hardening processes
03 · Audit

Internal and external audit

Conducting and coordinating audits, preparing for regulatory inspections.

  • Audit engagements on IT operations and projects
  • Coordination of internal and external audits
  • Quality assurance of audit work
04 · Risk

Data quality and risk governance

Management of IT risk and data quality, with clear reporting for senior management.

  • Data quality (BCBS 239)
  • Quarterly IT risk reporting
  • Process improvement (Six Sigma)

Certifications, education and languages

Proven skills

CISA

CISA

Certified Information Systems Auditor, ISACA. The international benchmark for information systems auditing.

27001

ISO/IEC 27001 Foundation

Fundamentals of the information security management system.

6σ

Six Sigma Black Belt

Leading process improvement projects, based on measurement.

ITIL

ITIL v3

IT service management best practice.

1991 – 1992

ICN Business School

DESS (Master's degree) in Information Systems Audit and Design

1989 – 1991

University of Lorraine

MIAGE (Master's in Computer Science applied to Business Management)

1987 – 1989

Faculty of Law, Economics and Management, Nancy

DEUG (two-year university diploma) in Economics

French

Working language

English

Fluent

Spanish

B2

Contact me

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