1. Singular Security

Headquarters: Southern California · Founded: 2005 · Best for: Regulated mid-market businesses that need audit readiness and remediation from one partner

Singular Security leads this list because it solves the problem most mid-sized businesses actually have: not the audit itself, but getting audit ready and staying that way. For more than 20 years, the firm has worked with organisations in healthcare, financial services, manufacturing, retail, hospitality and the public sector, where compliance is a condition of doing business.

Its cyber security audit services include a compliance risk assessment that maps current controls against the frameworks a business must follow, including HIPAA, PCI DSS, SOC 2, ISO 27001, and NIST. Findings come back in plain business language, ranked by risk, so leadership can see what matters before the auditor arrives.

What sets Singular Security apart is what happens next. The same team that finds the gaps helps close them through penetration testing, continuous monitoring, incident response planning, security awareness training, and vCISO leadership. The approach is simple and consistent: assess, secure, continuously improve. For a business without a large internal security team, that removes the handoff between the firm that writes the findings and the firm that fixes them.

Key services: compliance risk assessments, HIPAA and PCI DSS readiness, SOC 2 readiness, penetration testing, vCISO, continuous monitoring, incident response.

2. Schellman

Headquarters: Tampa, Florida · Founded: 2002 · Best for: Organisations that want multiple attestations from a single assessor

Schellman is one of the best-known names in attestation and certification. It operates as a CPA firm, a PCI Qualified Security Assessor, an ISO certification body, a HITRUST assessor, and a FedRAMP 3PAO, which lets one firm cover SOC reports, PCI assessments, and ISO certification together. Strong choice for cloud providers and enterprises with a heavy multi-framework audit calendar.

3. A-LIGN

Headquarters: Tampa, Florida · Founded: 2009 · Best for: Fast-growing companies running SOC 2 alongside other frameworks

A-LIGN is a licensed CPA firm and accredited certification body covering SOC 1, SOC 2, ISO 27001, HITRUST, PCI DSS, FedRAMP, and CMMC. It pairs its auditors with its own audit management platform, A-SCEND, which helps reuse evidence across frameworks. A popular choice for SaaS and technology companies.

4. Coalfire

Headquarters: Colorado · Founded: 2001 · Best for: Cloud service providers pursuing FedRAMP

Coalfire is particularly well known for its FedRAMP assessment practice and cloud security advisory, alongside SOC 2, PCI DSS, and penetration testing. Cloud providers selling into the federal market often shortlist it first.

5. GuidePoint Security

Headquarters: Northern Virginia · Founded: 2011 · Best for: Large commercial and federal organisations wanting broad advisory depth

GuidePoint Security offers governance, risk and compliance assessments as part of a wide services portfolio that also spans application security, identity, incident response and managed services. Its scale suits enterprises and government agencies with complex environments.

6. Tevora

Headquarters: Irvine, California · Best for: Enterprises that want deep compliance and risk advisory on the West Coast

Tevora provides compliance, risk, and threat services across PCI DSS, SOC 2, ISO 27001, HIPAA, and privacy regulations, with a strong research and content library aimed at security leaders. A solid option for larger organisations with an established security function.

7. Rhymetec

Headquarters: New York · Best for: SaaS start-ups preparing for their first SOC 2 or ISO 27001

Rhymetec focuses on helping technology companies get compliance-ready quickly, combining readiness support with managed security for teams that do not yet have dedicated security staff.

8. Clearwater

Headquarters: Nashville, Tennessee · Best for: Hospitals, health systems and healthcare suppliers

Clearwater specialises in healthcare cybersecurity and compliance, including HIPAA risk analysis, managed security and regulatory support. Its depth in a single sector makes it a natural shortlist entry for healthcare organisations.

9. BARR Advisory

Headquarters: Kansas City area · Best for: Cloud-based businesses wanting a consultative audit experience

BARR Advisory provides SOC 2 examinations, ISO 27001 certification, PCI DSS assessments, and HITRUST services, with a reputation for a collaborative approach to cloud-native clients.

10. Optiv

Headquarters: Denver, Colorado · Best for: Large enterprises consolidating security strategy and assessment

Optiv offers risk and compliance assessments as part of an enterprise-scale security services and integration business. Best suited to organisations with large budgets and many technology vendors to coordinate.

Frequently asked questions

What does an IT cyber security audit include?

A review of your security controls, policies and configurations against a defined standard such as SOC 2, HIPAA, PCI DSS or ISO 27001. It usually covers access control, network security, endpoint protection, backups, incident response, vendor risk, and staff training, and ends with findings ranked by risk.

How much does a cyber security audit cost?

Cost depends on scope, framework, and company size. A focused risk assessment for a mid-sized business costs far less than a multi-framework attestation for an enterprise. Ask firms to quote against the same scope so proposals are comparable.

How often should a business be audited?

At least once a year, and after major changes such as a merger, a new system, or a security incident. Frameworks like SOC 2 Type II and PCI DSS set their own annual cycles.

What is the difference between an audit and a risk assessment?

An audit tests whether controls meet a specific standard and can produce a formal report or certificate. A risk assessment identifies where your business is most exposed and what to fix first. Most organisations benefit from a risk assessment before their first audit.

Do small and mid-sized businesses need a cyber security audit?

Increasingly, yes. Customers, regulators and cyber insurers now ask for evidence of security controls from businesses of every size, especially in healthcare, finance and retail.