Fractional CISO for PE-Backed Portfolio Companies During Due Diligence and the Hold Period

Private equity due diligence has sharpened considerably on security in recent years. It is no longer a box-ticking appendix to commercial and financial due diligence, it is frequently its own workstream, with dedicated advisers reviewing data handling, incident history, access controls and compliance posture before a deal completes. For a portfolio company without a credible security function, that scrutiny does not stop being a problem once the deal closes. It becomes a running theme for the entire hold period.

What due diligence actually looks for

PE due diligence teams are typically looking for evidence, not assurances. A verbal statement that "we take security seriously" carries no weight against a documented risk register, a tested incident response plan, and a clear record of who owns security decisions inside the business. The gaps that show up most often are structural rather than technical: no named security owner, no current risk assessment, access controls that have not kept pace with headcount growth, and no clear record of supplier and third-party risk.

These gaps rarely kill a deal outright, but they do show up in the numbers, either as a valuation adjustment, a condition attached to completion, or a remediation item the new owners expect fixed fast. A business that walks into due diligence with this already in order controls that conversation rather than reacting to it.

What changes during the hold period

Once a deal completes, the security conversation does not end, it usually intensifies. Most PE value creation plans now include a security and risk workstream as standard, because the fund's own investors increasingly expect it, and because a security failure inside a portfolio company is now understood to be a fund-level reputational and financial risk, not just a company-level one.

This typically means: regular security reporting into the investment committee, not just the portfolio company board; a defined improvement plan with milestones, often tied to the wider 100-day and value creation plan; and, where the portfolio includes multiple companies, some consistency of approach so the fund can compare risk posture across its holdings rather than assessing each company from scratch.

A portfolio company without dedicated security leadership usually struggles with all three, not because the work is impossible, but because nobody senior enough owns it, and IT teams under operational pressure rarely have the bandwidth or remit to build board-level reporting on top of their day job.

Where a fractional CISO fits

A fractional CISO is well suited to both phases of this cycle, and for similar reasons the model fits scaling businesses generally: senior experience, engaged at the intensity the situation actually requires, without a full-time cost that a fund managing multiple portfolio companies is unlikely to want to carry in every one of them.

Before a deal, a fractional CISO can prepare a business for the security workstream of due diligence directly: building or tightening the risk register, documenting the incident response plan, closing the most visible access control gaps, and preparing the evidence pack a due diligence team will expect to see. This is the difference between due diligence surfacing problems and due diligence confirming they've already been handled.

During the hold period, a fractional CISO gives the portfolio company a consistent point of accountability for security, someone who reports to the board and, where required, into the investment committee, in the same commercial language the rest of the value creation plan is already reported in. For funds running this model across several portfolio companies, a fractional approach also makes it realistic to bring broadly consistent security leadership and reporting structure across the portfolio, without asking every company to independently build and fund the same function from scratch.

The practical case

For a portfolio company, the argument is straightforward: security due diligence findings and hold-period security failures both show up eventually, in valuation, in exit readiness, or in an incident that becomes the fund's problem as well as the company's. A fractional CISO addresses both ends of that risk, before a deal and throughout the hold, without requiring every portfolio company to carry the cost of a full-time executive hire on its own.