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SecurityWeek identified 40 cybersecurity-related M&A transactions announced in September 2025. The month’s most visible deals centered on AI security, OT protection, security-data infrastructure, email security and platform expansion. The list also included managed services, compliance, training, healthcare security, identity and adjacent technology businesses, so the count is broader than pure-play cybersecurity software acquisitions.
The headline transaction was Mitsubishi Electric’s agreement to buy the Nozomi Networks shares it did not already own. Other strategically important announcements included Check Point–Lakera, CrowdStrike–Pangea, F5–CalypsoAI, SentinelOne–Observo AI and Varonis–SlashNext.
How to read the 40-deal count
The figure comes from SecurityWeek’s September roundup, published October 7, 2025. It is an editorial count, not an official industry census.
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Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →“Announced” generally refers to a transaction being publicly disclosed or agreed, not necessarily completed. The roundup combines full-company acquisitions, agreements to acquire, asset or business purchases, services transactions and at least one majority-stake investment. It also includes cybersecurity-adjacent companies such as compliance, training, media, managed-service and consulting businesses. The table below follows SecurityWeek’s names and classifications.
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That scope matters. A majority investment is not equivalent to a 100% acquisition, and a signed agreement is not the same as a completed transaction. Where later closing information is available, it is shown separately.
The headline transactions
Mitsubishi Electric agreed to acquire Nozomi Networks
On September 9, Mitsubishi Electric announced an agreement to acquire the approximately 93% of Nozomi Networks that it did not already own. Nozomi provides operational-technology and industrial-control-system security. Mitsubishi Electric said the combination would connect its industrial and infrastructure presence with Nozomi’s OT-security technology and customer base.
Mitsubishi Electric’s later securities filing stated that the consideration for the remaining shares was approximately $883 million. This is different from describing the transaction broadly as an approximately $1 billion deal: the $883 million figure concerns the stake being acquired, not necessarily an enterprise-value or total-company valuation. The announcement was an agreement, with closing planned within the fiscal year ending March 31, 2026. Mitsubishi Electric announcement · securities filing
Check Point agreed to acquire Lakera
Check Point announced the Lakera deal on September 16. Lakera’s technology focuses on protecting AI applications and agents, including runtime protection and AI red teaming. Check Point described the acquisition as part of an end-to-end AI-security strategy and said it would establish a global AI-security center of excellence.
Check Point’s announcement did not disclose consideration. SecurityWeek cited a reported price of approximately $300 million; that figure should not be treated as company-confirmed consideration. Check Point later reported that the acquisition closed on October 22, 2025. announcement · closing disclosure
CrowdStrike agreed to acquire Pangea
Also announced September 16, CrowdStrike’s Pangea transaction targeted protection across enterprise-AI development, agents, identities, infrastructure and interactions. The announcement did not state a purchase price.
SecurityWeek cited a reported estimate of approximately $260 million. CrowdStrike’s later fiscal-2026 filing provides more precise accounting information: the company acquired Pangea on September 26 for consideration consisting principally of $212.1 million in cash, net of acquired cash, together with replacement equity and liability awards. The accounting disclosure is preferable to the earlier estimate when describing the completed transaction, while noting that total consideration was not limited to cash. announcement · filing
F5 completed its CalypsoAI acquisition
F5 announced an agreement to acquire CalypsoAI for $180 million, according to SecurityWeek. CalypsoAI brought AI-security capabilities involving agentic-AI red teaming, runtime defenses and automated enforcement. F5 announced completion on September 29 and said the capabilities would be introduced as F5 AI Guardrails and F5 AI Red Team. F5’s completion and product-integration announcement
SentinelOne agreed to acquire Observo AI
SentinelOne announced the Observo AI deal on September 8. Observo focuses on telemetry pipelines, data streaming, enrichment and high-volume security-data ingestion. SentinelOne said the acquisition would strengthen the data foundation of its Singularity Platform and support SIEM and security operations.
Financial terms were not disclosed in SentinelOne’s announcement. SentinelOne announcement
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Varonis acquired SlashNext
Varonis announced its SlashNext transaction on September 2. SlashNext provides AI-native email and collaboration-app security aimed at phishing, spearphishing and social-engineering attacks. The deal extends Varonis’s data-security and managed-detection capabilities toward an earlier attack vector.
SecurityWeek reported a price of $150 million. Varonis’s own announcement emphasizes the strategic combination but does not disclose that amount, so it should be attributed to the roundup rather than presented as an officially disclosed purchase price. Varonis announcement
Other notable platform deals
Cato Networks agreed to acquire Aim Security, adding AI-security capabilities to its networking and security platform. DigiCert acquired Valimail in email authentication and DMARC. SecurityScorecard acquired HyperComply to strengthen security-questionnaire and compliance workflows. Accenture acquired IAMConcepts, adding identity and access-management expertise to its services business.
Complete list of transactions
The following table reproduces the 40 buyer-target entries in SecurityWeek’s roundup. Unless a later closing is specifically identified above, “announced” describes the September disclosure rather than confirmed completion. Values marked “reported” are estimates or figures attributed by the roundup, not necessarily official consideration.
| Date | Buyer | Target | Segment or rationale | Type/status | Value |
|---|---|---|---|---|---|
| Sep. 2025 | Accenture | IAMConcepts | Identity and access management | Announced acquisition | Undisclosed |
| Sep. 2025 | Cato Networks | Aim Security | AI security | Announced acquisition | Reported estimate: $300–350 million |
| Sep. 16 | Check Point | Lakera | Agentic-AI security | Announced; later reported closed Oct. 22 | Reported estimate: about $300 million |
| Sep. 16 | CrowdStrike | Pangea | Enterprise-AI security | Announced; later accounting records closing Sep. 26 | Reported estimate: about $260 million; later filing: $212.1 million net cash plus other consideration |
| Sep. 2025 | DigiCert | Valimail | Email authentication and DMARC | Announced acquisition | Undisclosed |
| Sep. 2025 | F5 | CalypsoAI | AI guardrails and red teaming | Announced; completed Sep. 29 | $180 million, as reported by SecurityWeek |
| Sep. 9 | Mitsubishi Electric | Nozomi Networks | OT and IoT security | Agreement to acquire remaining shares | About $883 million for remaining 93% stake |
| Sep. 2025 | SecurityScorecard | HyperComply | Security questionnaires and compliance | Announced acquisition | Undisclosed |
| Sep. 8 | SentinelOne | Observo AI | Telemetry pipelines and SIEM | Announced acquisition | Undisclosed |
| Sep. 2 | Varonis | SlashNext | Email and collaboration security | Announced acquisition | $150 million, as reported by SecurityWeek |
| Sep. 2025 | 31 Concept | Xynthor AI | Cybersecurity and AI technology | Announced acquisition | Undisclosed |
| Sep. 2025 | 360 Advanced | Security Compliance Associates | Compliance and cybersecurity services | Announced acquisition | Undisclosed |
| Sep. 2025 | Aikido Security | Allseek and Haicker | Security-platform expansion | Two target entries; announced | Undisclosed |
| Sep. 2025 | American Systems | Epsilon | Cybersecurity services | Announced acquisition | Undisclosed |
| Sep. 2025 | Axiom GRC | The DPO Centre | Privacy and GRC | Announced acquisition | Undisclosed |
| Sep. 2025 | BID Equity | TinyMDM | Mobile-device management | Announced acquisition | Undisclosed |
| Sep. 2025 | CloserStill Media | Billington CyberSecurity | Cybersecurity media and events | Announced acquisition | Undisclosed |
| Sep. 2025 | CompassMSP | Simplegrid | Managed IT and security services | Announced acquisition | Undisclosed |
| Sep. 2025 | Com Laude | Markmonitor | Domain and brand protection | Announced acquisition | Undisclosed |
| Sep. 2025 | Cyberbit | RangeForce | Cyber ranges and security training | Announced acquisition | Undisclosed |
| Sep. 2025 | EbankIT | SecuritySide | Cybersecurity services | Announced acquisition | Undisclosed |
| Sep. 2025 | EchoStor | CyberNorth | Cybersecurity services | Announced acquisition | Undisclosed |
| Sep. 2025 | Fairdinkum Consulting | Tech 2020 Solutions | IT and security consulting | Announced acquisition | Undisclosed |
| Sep. 2025 | Fortified Health Security | Latitude | Healthcare cybersecurity | Announced acquisition | Undisclosed |
| Sep. 2025 | Hack The Box | LetsDefend | Cybersecurity training | Announced acquisition | Undisclosed |
| Sep. 2025 | Halon | Eleven | Email security | Announced acquisition | Undisclosed |
| Sep. 2025 | Harness | Qwiet AI | Application security | Announced acquisition | Undisclosed |
| Sep. 2025 | IDtech | OwnID | Identity | Announced acquisition | Undisclosed |
| Sep. 2025 | Scope Technologies | Plurilock Security / Cloud Codes | Cybersecurity technology | Announced acquisition | Undisclosed |
| Sep. 2025 | SDG Corporation | Hub City Media | IAM and consulting | Announced acquisition | Undisclosed |
| Sep. 2025 | Seclab | Seckiot | OT and IoT security | Announced acquisition | Undisclosed |
| Sep. 2025 | Spectrotel | Mosaic NetworX | Network and managed services | Announced acquisition | Undisclosed |
| Sep. 2025 | Spreedly | Dodgeball | Payments, identity and fraud-related security | Announced acquisition | Undisclosed |
| Sep. 2025 | Sunstone Partners | Clearwater | Healthcare cybersecurity and compliance | Majority-stake investment | Undisclosed |
| Sep. 2025 | Tego | VigilAigent | Cybersecurity and threat intelligence | Announced acquisition | Undisclosed |
| Sep. 2025 | Thrive | VitalCORE | Managed services and security | Announced acquisition | Undisclosed |
| Sep. 2025 | UltraViolet Cyber | Black Duck’s Application Security Testing Services | Application-security services/assets | Asset or business acquisition | Undisclosed |
| Sep. 2025 | Unico | OwnID | Identity | Announced acquisition | Undisclosed |
| Sep. 2025 | Wysetek Systems | Scalezee Technologies | IT and security services | Announced acquisition | Undisclosed |
Quality note: SecurityWeek’s published list contains two OwnID buyer-target pairings and counts Aikido Security’s two targets as separate entries. Those classifications are retained here rather than silently consolidating or correcting them.
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What the transactions say about the market
AI security was the clearest headline theme
Check Point, CrowdStrike and F5 each bought capabilities around the security of AI applications, agents or model interactions. Lakera emphasized runtime protection and AI red teaming; Pangea addressed detection and response across enterprise-AI environments; and CalypsoAI contributed guardrails, testing and enforcement. SentinelOne’s Observo AI deal targeted a less visible but crucial layer: the telemetry pipelines that feed SIEM and security operations.
These are related but different acquisition theses. The deals do not establish that AI security represented a majority of all 40 transactions. They show that it was the most visible strategic theme among the larger vendor announcements.
OT security attracted industrial capital
Nozomi was notable not only for its size but also for the buyer. Mitsubishi Electric is an industrial-technology company, not a conventional cybersecurity consolidator. The deal reflects the strategic importance of protecting manufacturing, power, rail and other critical infrastructure environments. It also suggests that OT security can be treated as an operating capability embedded in industrial platforms, rather than solely as a software category sold by security vendors.
Platforms bought missing layers
Several deals fit a “buy the missing layer” pattern: Varonis added email and collaboration protection; DigiCert added email-authentication capabilities; SentinelOne added data-pipeline infrastructure; SecurityScorecard added questionnaire automation; and Accenture added IAM delivery expertise. The rationale is less about buying a direct competitor than broadening the control surface, improving distribution or filling a product gap.
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The long tail remained fragmented
Beyond AI and OT, the list spans identity, GRC, privacy, healthcare security, application testing, managed security, MSPs, cyber ranges, workforce training, domain protection and compliance consulting. That breadth is important for investors and corporate-development teams: consolidation was occurring in services and channel businesses as well as in venture-backed security software.
Best Value
Deal values: what can and cannot be compared
Only a minority of the 40 entries had publicly discussed values. The figures also use different concepts: consideration for a remaining stake, cash consideration, total consideration including equity awards, enterprise value and press estimates.
- Company or filing disclosure: Mitsubishi Electric’s approximately $883 million for Nozomi’s remaining shares and CrowdStrike’s later accounting disclosure of $212.1 million in net cash plus other consideration.
- Reported estimate: the approximately $300 million Lakera figure, approximately $260 million Pangea estimate, $300–350 million Aim Security estimate, $180 million CalypsoAI figure attributed by SecurityWeek and $150 million SlashNext figure attributed by SecurityWeek.
- Undisclosed: most of the remaining transactions.
These amounts should not be added into a single September “total.” They are not comparable measures, and reported estimates may differ from final consideration. Private-company buyers and sellers frequently disclose only that an agreement was reached.
Why transaction status matters
A September announcement can represent a signed agreement, a completed acquisition, an asset purchase or a majority investment. The distinction affects ownership, integration, valuation and the buyer’s ability to direct the target’s operations.
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Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallFor example, F5 announced completion of CalypsoAI on September 29. CrowdStrike’s later filing records a September 26 closing for Pangea, while Check Point later reported Lakera closing on October 22. Those dates should not be backdated to the original announcement dates. Sunstone Partners’ Clearwater transaction should likewise be described as a majority-stake investment, not automatically as a full acquisition.
Bottom line for market watchers
September 2025 was a busy month for cybersecurity-related M&A, but its significance lies in the mix rather than the headline count alone. Large vendors were buying AI-security, OT-security and security-operations capabilities to extend broader platforms, while industrial, services, channel and private-equity buyers continued consolidating adjacent markets. The most reliable analysis separates announced agreements from completed deals, confirmed consideration from reported estimates, and pure-play cybersecurity acquisitions from the wider ecosystem of compliance, training and managed services.
For ongoing deal tracking, record the announcement date, closing date, transaction type, buyer category, target segment, consideration source and primary announcement for every entry. That schema prevents a reported valuation or an agreement announcement from being mistaken for a final purchase price or completed transaction.
Quick Recap
Sources
- SecurityWeek: Cybersecurity M&A Roundup — 40 Deals Announced in September 2025
- Check Point–Lakera announcement
- CrowdStrike–Pangea announcement
- Mitsubishi Electric–Nozomi announcement
- SentinelOne–Observo AI announcement
- Varonis–SlashNext announcement
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