In Mergers & Acquisitions (M&A) the focus is usually on financial, legal, and operational aspects.
Yet cybersecurity has become one of the decisive factors that can make or break the entire deal.
According to IBM, 60% of companies suffer a security incident within 12 months of completing a merger or acquisition.
Why Cybersecurity Is Critical in M&A
During an M&A transaction:
- organisations merge systems, data, and processes,
- differing security standards and configurations create new vulnerabilities,
- access to highly sensitive financial, legal, and personal data is dramatically expanded.
Each of these elements significantly increases the risk of cyberattacks, data theft, or sabotage.
Cyber risk management must therefore be an integral part of the due-diligence process.
Primary Cybersecurity Challenges in M&A
- Disparate security maturity – companies often operate with very different policies and protection levels.
- IT system integration – merging infrastructures and applications frequently introduces misconfigurations and new attack surfaces.
- Elevated incident risk – organisational changes and shifting permissions are favourite moments for threat actors.
The most exposed sectors are finance, technology, and healthcare — due to the high value of the data involved.
How to Assess Cyber Risk Before Closing the Deal
- Security audit / cyber due diligence – perform a thorough evaluation of both parties’ cybersecurity posture before signing.
- Asset & data mapping – identify critical systems, data sets, and processes that require special protection.
- Controlled access during due diligence – enforce strict rules for data rooms and temporary system access.
Managing Security Throughout Post-Merger Integration
- Unified security standards – harmonise policies, tools, and configurations across the new entity.
- Employee training – ensure everyone understands the new security procedures and expectations.
- Continuous post-merger monitoring – actively watch for anomalies and run penetration tests after integration.
Most attacks do not occur during the transaction — they happen after integration, when attention shifts back to day-to-day business.
Cyber Due Diligence – Best-Practice Framework
| Phase | Key Action | Goal |
|---|---|---|
| Pre-M&A | Full security audit of both organisations | Identify risks and hidden liabilities |
| During Deal | Strict data-access & transfer protocols | Prevent leaks of deal-sensitive information |
| Post-M&A | Monitoring, penetration testing, policy alignment | Achieve consistent, resilient security posture |
Why Boards and Executives Must Care
A data breach during or after M&A can:
- materially reduce deal value,
- trigger regulatory fines (GDPR, NIS2, SEC rules),
- destroy brand reputation and investor confidence.
Cyber risk management must be embedded in the M&A strategy from day one.
Get in Touch
I assist companies with cyber due diligence, IT/OT risk assessments, and secure post-merger integration in full alignment with ISO 27005 and NIST RMF.
Email: biuro@wichran.pl
Phone: +48 515 601 621
Author: Piotr Wichrań – Court-appointed IT forensic expert, IT/OT cybersecurity specialist, licensed private investigator
@Informatyka.Sledcza