Best Cybersecurity Due Diligence Firms for M&A in 2026: Top 6 Compared
Quick Answer
The best cybersecurity due diligence firms for M&A in 2026 segment by deal type. Mandiant (Google Cloud) ($30-200k+/engagement, $5.4B Google acquisition 2022) is industry standard for $50M+ deals. CrowdStrike Services (NASDAQ: CRWD, $25-150k+) combines DD + post-close Falcon monitoring. NCC Group ($20-120k+, Manchester UK) is the independent technical-depth choice. Bishop Fox ($20-80k+, Tempe AZ) specializes in application + cloud security for tech / SaaS M&A. BlueVoyant ($15-100k+, NYC) specializes in third-party + supply-chain risk. Optiv ($30-200k+, ~$1B+ revenue) is the largest US cybersecurity services firm. Choose based on deal industry + cyber-risk profile.
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Cybersecurity due diligence is a critical layer of M&A diligence, especially for deals over $25M EV or for tech-enabled / data-heavy businesses. In 2026, the cyber DD market includes pure-play independent firms, platform-vendor service arms (Mandiant/Google, CrowdStrike), and specialist boutiques.
Choosing the right cyber DD firm matters because (1) undetected breaches cost $4M+ on average (IBM 2023 data), (2) data-privacy regulations (GDPR, CCPA) shift risk to acquirer post-close, (3) different deal types have different cyber-risk profiles (SaaS = application security; manufacturing = supply-chain risk).
This guide compares 6 leading cyber DD firms.
What this guide covers
- Mandiant (Google Cloud, $30-200k+) is industry standard for $50M+ deals.
- CrowdStrike Services (NASDAQ: CRWD, $25-150k+) combines DD + post-close monitoring.
- NCC Group ($20-120k+, UK) is the independent technical-depth choice.
- Bishop Fox ($20-80k+) specializes in tech / SaaS application security.
- BlueVoyant ($15-100k+) specializes in supply-chain risk.
- Optiv ($30-200k+) is the largest US cyber services firm.
- Match firm to deal industry + cyber-risk profile.
Comparison: top 6 options at a glance
| Vendor | Best for | Pricing range | HQ | Key feature |
|---|---|---|---|---|
| Mandiant (Google Cloud) | Enterprise M&A cyber DD | $30-200k+/engagement | Reston, VA (Google Cloud subsidiary) | Industry-standard incident-response + DD |
| CrowdStrike Services | M&A cyber DD + post-close monitoring | $25-150k+/engagement | Austin, TX (NASDAQ: CRWD) | Combined DD + post-close monitoring |
| NCC Group | Independent cyber DD + technical assessments | $20-120k+/engagement | Manchester, UK + US ops | Independent technical depth |
| Bishop Fox | Application + cloud security DD | $20-80k+/engagement | Tempe, AZ | Application + cloud security specialist |
| BlueVoyant | Third-party + supply chain cyber DD | $15-100k+/engagement | NYC, NY | Third-party + supply-chain risk specialist |
| Optiv | Enterprise cyber DD + advisory | $30-200k+/engagement | Denver, CO | Largest US cybersecurity services firm |
How we evaluated
- Deal size. $50M+ deals: Mandiant, CrowdStrike, Optiv. $5-50M: NCC Group, Bishop Fox, BlueVoyant.
- Industry risk profile. Tech / SaaS: Bishop Fox. Manufacturing / distribution: BlueVoyant. Enterprise: Mandiant / CrowdStrike / Optiv.
- Independence vs. platform-vendor. Independent (no vendor lock-in): NCC Group, Bishop Fox. Platform-vendor: Mandiant (Google), CrowdStrike Falcon.
- Post-close monitoring. Combined DD + monitoring: CrowdStrike Falcon. DD-only: most others.
Mandiant (Google Cloud)
Mandiant (Google Cloud subsidiary after 2022 $5.4B acquisition) is the industry-standard cyber due diligence firm. Strong adoption for $50M+ M&A deals.
- Industry standard for cyber DD.
- Best-in-class threat intelligence.
- Google Cloud-backed scale.
- Strong incident-response history.
- Premium pricing ($30-200k+).
- Slower than boutique firms.
- Enterprise-focused.
When Mandiant (Google Cloud) is the right choice: you’re a Fortune 500 corp dev team or large PE platform doing $50M+ M&A.
CrowdStrike Services
CrowdStrike Services (NASDAQ: CRWD, ~$3B+ revenue) offers cyber DD + post-close monitoring through Falcon platform. Strong adoption among PE platforms doing tech-heavy M&A.
- Combined DD + post-close monitoring.
- Best-in-class EDR (endpoint detection).
- Strong CrowdStrike Falcon platform ecosystem.
- Continuous post-close protection.
- Pricing scales with platform adoption.
- Less specialized than Mandiant for pure DD.
When CrowdStrike Services is the right choice: you’re a PE platform wanting cyber DD + post-close Falcon endpoint monitoring.
NCC Group
NCC Group is the UK-rooted independent cyber DD firm. Strong adoption among European PE and US mid-market M&A.
- Independent (not tied to platform vendor).
- Deep technical assessment expertise.
- Strong UK + European presence.
- Good code-review + pen-testing.
- Smaller US footprint than Mandiant / CrowdStrike.
- UK timezone for US deals can slow process.
When NCC Group is the right choice: you want independent cyber DD without vendor platform lock-in, especially for European deals.
Bishop Fox
Bishop Fox specializes in application + cloud security DD. Strong adoption for tech / SaaS M&A where application security depth matters.
- Application + cloud security specialist.
- Strong pen-testing + red-team expertise.
- Modern UX + reporting.
- Good for SaaS / tech M&A.
- Less broad than Mandiant for full enterprise DD.
- Focus on application layer.
When Bishop Fox is the right choice: you’re doing tech / SaaS M&A where application + cloud security is the primary risk.
BlueVoyant
BlueVoyant specializes in third-party + supply-chain cyber risk. Strong adoption for M&A in supply-chain-heavy industries (manufacturing, distribution, retail).
- Third-party + supply-chain specialist.
- Strong for manufacturing / distribution M&A.
- External-attack-surface assessments.
- Growing brand.
- Less depth on application or internal security than Mandiant / Bishop Fox.
When BlueVoyant is the right choice: you’re doing M&A in manufacturing / distribution / retail where supply-chain risk is material.
Optiv
Optiv is the largest US cybersecurity services firm (~$1B+ revenue). Strong adoption for Fortune 500 corp dev cyber DD.
- Largest US cyber services firm by revenue.
- Broad multi-vendor expertise.
- Strong enterprise client base.
- Premium pricing.
- Larger / more bureaucratic than boutiques.
When Optiv is the right choice: you’re a Fortune 500 corp dev team wanting broad enterprise cyber DD.
How to choose: buying criteria
1. Match firm to deal size
$50M+ deals: ‘Big’ firms (Mandiant, Optiv). $5-50M: independent boutiques (NCC, Bishop Fox, BlueVoyant).
2. Match firm to deal industry
Tech / SaaS: Bishop Fox. Manufacturing / supply chain: BlueVoyant. Enterprise: Mandiant / CrowdStrike.
3. Plan for post-close monitoring
If you want ongoing post-close cyber monitoring, CrowdStrike Falcon (DD-to-monitoring transition) is efficient.
4. Negotiate scope + timeline
DD scopes range from external-only (1-2 weeks) to full internal + application + supply-chain (4-8 weeks). Match scope to deal complexity.
Dangers and traps when selecting
1. Skipping cyber DD on tech-enabled deals
Undetected breaches cost $4M+ on average. Skip = uncovered risk.
2. Wrong-vertical specialist
Generalist firm on a SaaS deal misses application risk.
3. Insufficient scope
External-only scan misses internal threats.
4. Post-close gap
DD discovers issues; without post-close remediation plan, gaps persist.
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About the Author
Christoph Totter is the founder of CT Acquisitions, a buy-side partner headquartered in Sheridan, Wyoming. We work directly with 100+ buyers, search funders, family offices, lower middle-market PE, and strategic consolidators, including direct mandates with the largest consolidators that other intermediaries cannot access. The buyers pay us when a deal closes, not the seller. No retainer, no exclusivity, no contract until close. Connect on LinkedIn · Get in touch
Frequently asked questions
What is cybersecurity due diligence?
Cyber DD is the layer of M&A diligence that assesses cybersecurity risk in a target: existing breaches, vulnerabilities, compliance gaps, third-party risk, and post-close remediation needs. Critical for $25M+ deals or tech-enabled / data-heavy businesses.
Who are the best cyber DD firms?
Mandiant (Google Cloud, $30-200k+/engagement), CrowdStrike Services (NASDAQ: CRWD, $25-150k+), NCC Group ($20-120k+), Bishop Fox (tech / SaaS specialist, $20-80k+), BlueVoyant (supply chain specialist, $15-100k+), Optiv (~$1B+ revenue, $30-200k+).
How much does cyber DD cost?
Range: $15-200k+/engagement depending on scope + firm. External-only scans: $5-25k. Full internal + application + supply-chain: $50-200k+.
When is cyber DD critical?
Critical for deals over $25M EV, tech-enabled businesses, data-heavy industries (healthcare, FinServ, retail), supply-chain-heavy industries (manufacturing, distribution), regulated industries (financial services, healthcare).
Does CT Strategic Partners coordinate cyber DD?
Yes, on retained buy-side mandates, we coordinate cyber DD as part of full diligence package. We typically introduce buyers to NCC Group or Bishop Fox for mid-market, Mandiant / CrowdStrike for larger deals.