Global M&A rebounded sharply in 2025, reaching about $4.8 trillion in deal value, which Bain described as the second-highest total on record. McKinsey also reported that M&A activity reached 4.2% of total market value in 2025, up from 3.3% in 2024. Deals are moving again. But as activity picks up, one question still gets answered too late: what is actually running on the target network, and what state is it in?
That question sits at the heart of cybersecurity asset visibility in M&A. Deloitte says the ability to identify and manage cyber exposure before closing a deal is becoming increasingly relevant as acquirers look to protect value. In practice, that means going beyond assumptions and self-reported inventories to build a clear picture of the systems, assets and exposures that will become yours on day one.
Half of M&A Security Incidents Are Not Malicious
One of the most useful reminders in recent M&A cyber research comes from ReliaQuest. In its analysis of customer data from 2024, only half of M&A-related security incidents involved malicious activity. The rest were linked to policy and compliance issues, difficulties baselining internal tools, and investigation delays triggered by integration.
That matters because it shifts the conversation. Not every post-deal security issue starts with an attacker. Many start with uncertainty. Teams do not know exactly what they have inherited. They struggle to compare the acquired environment with their own. They discover too late that controls do not align, inventories are incomplete, or critical systems sit outside normal monitoring. This is where asset visibility becomes a commercial issue as much as a technical one.
ReliaQuest also found that manufacturing accounted for 42% of customer M&A incidents in its dataset, and said this likely relates to the sector’s reliance on legacy systems and operational technology, both of which make updates, monitoring and incident response harder during periods of change.
The Inheritance Problem
When a deal closes, the technical reality changes immediately. You are no longer assessing a target from the outside. You are inheriting an attack surface. That includes managed devices, unmanaged devices, cloud assets, legacy systems and the blind spots between them.
The wider cyber environment is not standing still either. The World Economic Forum’s Global Cybersecurity Outlook 2026 says organisations are facing a risk landscape reshaped by accelerating AI adoption, geopolitical fragmentation and widening cyber inequity. For M&A teams, that makes pre-close visibility even more important, because inherited exposure is landing in a more complex operating environment than ever.
runZero’s 2025 Undead by Design report adds useful evidence here. Across the enterprises it studied, 8.56% of assets were running an end-of-life operating system, while 5.00% were already beyond extended end of life and therefore unable to receive timely critical patches. In an M&A scenario, those are not abstract numbers. They are the kinds of assets an acquirer may inherit without fully understanding where they sit, what they support or how exposed they are.
What Good Due Diligence Looks Like
The strongest M&A cybersecurity programmes treat visibility as a pre-close priority, not a post-close clean-up task. That means validating what is actually present in the target environment rather than relying only on what has been documented internally. Deloitte frames this as part of a broader shift in due diligence, with cyber exposure now something acquirers are expected to identify and manage early enough to protect value.
A self-reported inventory tells you what a target believes it has. Independent discovery helps show what is really there, including systems that are difficult to scan, easy to overlook or disconnected from formal asset records. That matters most in environments with OT, IoT, legacy infrastructure and hybrid estates, where traditional visibility is often weakest. runZero says its platform provides agentless, credential-free visibility across managed and unmanaged assets spanning IT, OT, IoT and cloud.
Good cybersecurity asset visibility in M&A helps acquirers understand:
- the full asset inventory across the target environment
- which systems are unsupported or end of life
- where unmanaged or unexpected assets may sit
- which exposures could complicate integration or increase inherited risk after close
The Cost of Getting This Wrong
Cyber risk can influence deal value directly. PwC says cyber security can have a significant impact on business value across the lifecycle of an investment, which is why it needs to be considered at each stage of the deal process.
That is why cybersecurity asset visibility in M&A matters before the paperwork is signed. If buyers are making decisions based on incomplete inventories or assumptions about the target environment, they risk inheriting unsupported systems, unmanaged assets and hidden exposure that only becomes visible after close.
The Cost of Getting This Wrong
You cannot manage what you cannot see. In M&A, that is more than a security principle. It is a deal principle.
As deal activity returns at scale, the organizations best placed to manage cyber risk will be the ones that establish visibility early, before integration pressure builds and before blind spots become liabilities. The question is not whether a target environment contains hidden risk. The question is whether you will find it before the deal closes.
The runZero Platform was built for exactly this challenge. Agentless, credential-free and deployable in minutes, it helps security and IT teams build a clearer picture of the environment before the deal closes, during integration and after the combined business begins to settle.
Ready to see what's really in your network?
Global M&A rebounded sharply in 2025, reaching about $4.8 trillion in deal value, which Bain described as the second-highest total on record. McKinsey also reported that M&A activity reached 4.2% of total market value in 2025, up from 3.3% in 2024. Deals are moving again. But as activity picks up, one question still gets answered too late: what is actually running on the target network, and what state is it in?
That question sits at the heart of cybersecurity asset visibility in M&A. Deloitte says the ability to identify and manage cyber exposure before closing a deal is becoming increasingly relevant as acquirers look to protect value. In practice, that means going beyond assumptions and self-reported inventories to build a clear picture of the systems, assets and exposures that will become yours on day one.
Half of M&A Security Incidents Are Not Malicious
One of the most useful reminders in recent M&A cyber research comes from ReliaQuest. In its analysis of customer data from 2024, only half of M&A-related security incidents involved malicious activity. The rest were linked to policy and compliance issues, difficulties baselining internal tools, and investigation delays triggered by integration.
That matters because it shifts the conversation. Not every post-deal security issue starts with an attacker. Many start with uncertainty. Teams do not know exactly what they have inherited. They struggle to compare the acquired environment with their own. They discover too late that controls do not align, inventories are incomplete, or critical systems sit outside normal monitoring. This is where asset visibility becomes a commercial issue as much as a technical one.
ReliaQuest also found that manufacturing accounted for 42% of customer M&A incidents in its dataset, and said this likely relates to the sector’s reliance on legacy systems and operational technology, both of which make updates, monitoring and incident response harder during periods of change.
The Inheritance Problem
When a deal closes, the technical reality changes immediately. You are no longer assessing a target from the outside. You are inheriting an attack surface. That includes managed devices, unmanaged devices, cloud assets, legacy systems and the blind spots between them.
The wider cyber environment is not standing still either. The World Economic Forum’s Global Cybersecurity Outlook 2026 says organisations are facing a risk landscape reshaped by accelerating AI adoption, geopolitical fragmentation and widening cyber inequity. For M&A teams, that makes pre-close visibility even more important, because inherited exposure is landing in a more complex operating environment than ever.
runZero’s 2025 Undead by Design report adds useful evidence here. Across the enterprises it studied, 8.56% of assets were running an end-of-life operating system, while 5.00% were already beyond extended end of life and therefore unable to receive timely critical patches. In an M&A scenario, those are not abstract numbers. They are the kinds of assets an acquirer may inherit without fully understanding where they sit, what they support or how exposed they are.
What Good Due Diligence Looks Like
The strongest M&A cybersecurity programmes treat visibility as a pre-close priority, not a post-close clean-up task. That means validating what is actually present in the target environment rather than relying only on what has been documented internally. Deloitte frames this as part of a broader shift in due diligence, with cyber exposure now something acquirers are expected to identify and manage early enough to protect value.
A self-reported inventory tells you what a target believes it has. Independent discovery helps show what is really there, including systems that are difficult to scan, easy to overlook or disconnected from formal asset records. That matters most in environments with OT, IoT, legacy infrastructure and hybrid estates, where traditional visibility is often weakest. runZero says its platform provides agentless, credential-free visibility across managed and unmanaged assets spanning IT, OT, IoT and cloud.
Good cybersecurity asset visibility in M&A helps acquirers understand:
- the full asset inventory across the target environment
- which systems are unsupported or end of life
- where unmanaged or unexpected assets may sit
- which exposures could complicate integration or increase inherited risk after close
The Cost of Getting This Wrong
Cyber risk can influence deal value directly. PwC says cyber security can have a significant impact on business value across the lifecycle of an investment, which is why it needs to be considered at each stage of the deal process.
That is why cybersecurity asset visibility in M&A matters before the paperwork is signed. If buyers are making decisions based on incomplete inventories or assumptions about the target environment, they risk inheriting unsupported systems, unmanaged assets and hidden exposure that only becomes visible after close.
The Cost of Getting This Wrong
You cannot manage what you cannot see. In M&A, that is more than a security principle. It is a deal principle.
As deal activity returns at scale, the organizations best placed to manage cyber risk will be the ones that establish visibility early, before integration pressure builds and before blind spots become liabilities. The question is not whether a target environment contains hidden risk. The question is whether you will find it before the deal closes.
The runZero Platform was built for exactly this challenge. Agentless, credential-free and deployable in minutes, it helps security and IT teams build a clearer picture of the environment before the deal closes, during integration and after the combined business begins to settle.
