What Is a Fractional CISO?
A fractional CISO is a senior security executive who works with your company on a part-time basis — providing the same strategic leadership as a full-time Chief Information Security Officer at a fraction of the cost.
For Series A through mid-market companies, a fractional CISO is often the right answer to a SOC 2 deadline, investor security expectations, or enterprise customer questionnaire pressure — without the 3-to-6 month hiring process and $300K+ annual commitment of a full-time hire.
What a Fractional CISO Does
A fractional CISO owns your security program strategy and execution. They are not a consultant who produces a report and leaves — they are an embedded executive who is accountable for your security posture, named in customer security questionnaires, and present in board meetings.
The specific scope varies by engagement. The fractional CISO retainer at getaciso.ai includes approximately 20 hours/month of ongoing program leadership. Project-based engagements like SOC 2 readiness and AI security governance are fixed-scope with defined deliverables.
When Does a Company Need a Fractional CISO?
Most fractional CISO engagements are triggered by one of five events. If any of these sounds familiar, a fractional CISO can typically start within days — not months.
How Much Does a Fractional CISO Cost?
Fractional CISO retainers typically range from $3,000 to $15,000 per month, depending on hours, scope, and practitioner seniority. This compares to a full-time CISO salary of $250,000–$400,000 annually — before benefits, equity, and the 3-to-6 month time-to-hire.
All engagements are transparent and fixed-price where possible. There are no hourly overages on retainer scope, no hidden fees, and no junior staff markup. One practitioner, quoted directly.
Fractional CISO vs. vCISO vs. Full-Time CISO
The right model depends on your company size, compliance requirements, and how much continuity matters. Here is how the options compare.
| Dimension | Fractional CISO | vCISO (Firm) | Full-Time CISO |
|---|---|---|---|
| Cost | $3K–$15K/month | $3K–$12K/month (firm markup) | $250K–$400K/year + benefits |
| Who shows up | Same senior practitioner every time | Varies by firm — often rotates | One person, full-time |
| Hours/month | 10–20 hrs/month | 10–20 hrs/month | 160+ hrs/month |
| Time to start | Days | Weeks | 3–6 months to hire |
| Board reporting | Yes | Varies | Yes |
| Compliance ownership | Yes | Yes | Yes |
| Technical depth | Practitioner-dependent — verify credentials | Varies by assigned staff | Hire-dependent |
| Right for | Series A–mid-market (30–400 employees) | SMBs needing broad coverage | 400+ employees, regulated industries |
vCISO costs reflect firm-model pricing typical of managed security service providers. Individual practitioners vary. Full-time CISO salaries are US market estimates for technology companies (2025–2026).
What to Look for When Hiring a Fractional CISO
The fractional CISO market includes a wide range of practitioners. Here are the signals that separate credible candidates from policy writers who have never been accountable for a real audit.
Frequently Asked Questions
What is a fractional CISO?
A fractional CISO (Chief Information Security Officer) is a senior security executive who works with your company on a part-time or contract basis rather than as a full-time employee. They provide the same strategic security leadership — policy development, risk management, compliance oversight, board reporting — but at a fraction of the cost of a $250K–$400K full-time hire.
What is the difference between a fractional CISO and a vCISO?
The terms are often used interchangeably, but there is an important practical distinction. "vCISO" (virtual CISO) typically describes a consulting firm model where a team of staff is assigned to your account — often meaning different people show up each month. A fractional CISO is a single senior practitioner working part-time, consistently, on your account. You get the same executive for every engagement, every board meeting, and every audit.
How much does a fractional CISO cost?
Fractional CISO retainers typically range from $3,000 to $15,000 per month depending on scope and hours. At getaciso.ai, the fractional CISO retainer is $8,500/month for approximately 20 hours of senior security leadership. This compares to a full-time CISO salary of $250,000–$400,000 annually, plus benefits and equity. Project-based engagements (SOC 2 readiness, AI governance) run $8,500–$25,000 depending on scope.
When does a company need a fractional CISO?
The most common triggers are: a SOC 2 or ISO 27001 audit deadline driven by enterprise customers or investors; an AI governance gap flagged in vendor security questionnaires; a Series A or B milestone where investors or the board expect security leadership; or a security incident that exposed the absence of a documented security program. Most companies engaging a fractional CISO have 30–400 employees and no full-time security leader.
What does a fractional CISO actually do?
A fractional CISO owns the security program strategy and execution. In practice this includes: security policy and procedure development, risk register maintenance, SOC 2 / ISO 27001 / HIPAA compliance oversight, vendor risk assessments, incident response planning, and quarterly board or executive reporting. They also serve as the named CISO in enterprise customer security questionnaires and act as the accountability point for your security posture.
Can a fractional CISO replace a full-time CISO?
For most companies under 500 employees, yes — a fractional CISO provides the same strategic output at significantly lower cost. The decision to hire a full-time CISO typically makes sense when you exceed 400–500 employees, face a regulatory environment requiring a dedicated security executive (certain federal contracts, regulated financial services), or have a security team of 5+ that needs full-time leadership.
What should I look for when hiring a fractional CISO?
Look for a practitioner — not just a policy writer. The right fractional CISO should have hands-on experience with the compliance frameworks your company needs (SOC 2, ISO 27001, HIPAA), verifiable board-level communication experience, recognized industry credentials (CISSP, CISM), and ideally a track record you can verify: completed audits, published work, or speaking engagements at recognized security conferences.
Thirty minutes. Free. No pitch deck.
Tell me where your security program is today and what's driving urgency. I'll tell you honestly whether a fractional CISO is the right answer — and if so, what that looks like.