Cyber Risk Quantification with Claude — FAIR Model, ALE and Cyber Insurance Sizing

Why Cyber Risk Needs Financial Quantification

Cyber risk has long been managed in a language that boards and CFOs can't act on: "critical vulnerability," "high severity," "attack surface reduction." These terms mean something to security teams and nothing to the audit committee. A board that hears "we have 14 critical vulnerabilities" cannot make a capital allocation decision. A board that hears "unmitigated ransomware exposure represents $12M–$28M in expected annual loss — our current $5M deductible cyber policy leaves $7M to $23M uninsured" can.

FAIR (Factor Analysis of Information Risk) is the international standard for cyber risk quantification. It decomposes cyber risk into its component financial drivers and produces output in the only language that matters to the C-suite: dollars. Claude can help risk and finance teams apply FAIR methodology to their specific threat scenarios, build the supporting financial models, and communicate findings in board-ready formats.

The FAIR Model: Structure and Key Concepts

FAIR defines risk as the probable frequency and probable magnitude of future loss. The key building blocks:

• Loss Event Frequency (LEF): How often does a threat event lead to a loss? Decomposed into Threat Event Frequency (how often does an attacker try?) × Vulnerability (probability the attempt succeeds).
• Loss Magnitude: How much does each loss event cost? Six forms of loss: Productivity, Response, Replacement, Competitive Advantage, Fines & Judgments, Reputation.
• Annualized Loss Expectancy (ALE): LEF × Loss Magnitude. The expected annual financial impact, used for investment decisions.
• Value at Risk (VaR): FAIR outputs a Monte Carlo distribution of potential annual losses — the 90th percentile is the "tail risk" exposure for insurance sizing.

• "Run a FAIR analysis for the following ransomware scenario at a regional bank. Asset: core banking system (holds customer data for 240,000 accounts). Threat: ransomware group targeting financial services via phishing. Current controls: endpoint detection and response (EDR) deployed on 90% of workstations, email filtering, MFA on external-facing systems. Threat Event Frequency: industry data suggests 0.8 attempts per year for a bank this size. Vulnerability: with current controls, estimate 15% probability a successful phishing email leads to ransomware deployment. Loss components: (1) Business interruption: $180K/day revenue, estimated 4–14 day recovery range. (2) Incident response costs: $400K–$800K estimated. (3) Regulatory fine (NYDFS cyber regulation): $200K–$2M range based on similar incidents. (4) Customer notification and credit monitoring: $45 per affected customer. (5) Reputational loss: estimated 2–5% customer churn. Calculate ALE, 90th percentile annual loss, and the risk reduction value of adding immutable backups (reduces recovery time from 4–14 days to 1–3 days)."
• "Using FAIR, help me quantify the risk of a third-party data breach through our loan origination SaaS vendor. The vendor processes applications for 8,000 loans/year with full PII (SSN, income, employment). Breach frequency: I estimate 0.12 breaches per year at a vendor of this type and size based on Verizon DBIR data for financial services SaaS. Breach magnitude: CCPA statutory damages $100–$750/record, PII notification costs $5M, credit monitoring $500K, litigation costs $2M–$8M range. Produce a FAIR risk register entry with ALE and 95th percentile loss."

Cyber Insurance Sizing

Cyber insurance sizing is one of the most common applications of FAIR quantification. Underwriters want to know your EML (Estimated Maximum Loss) and your expected frequency. Buyers need to know whether their limits are adequate for their tail risk. Claude can model both sides of the conversation.

• "I need to right-size our cyber insurance policy. Current coverage: $10M limit, $500K retention. Our FAIR analysis shows: ALE $3.2M, 90th percentile annual loss $14.8M, 99th percentile (catastrophic scenario) $41M. The catastrophic scenario is a full IT outage affecting all business lines for 21 days plus a class-action lawsuit. Analyze: (1) Is our $10M limit adequate? (2) What limit would cover the 90th percentile scenario? (3) What is the cost-benefit of raising the limit from $10M to $20M if the additional premium is $280K/year? (4) What controls would most reduce the premium based on underwriter scoring factors?"
• "Draft the cyber insurance application section on 'Information Security Controls' for a 500-person financial services firm. We have: SOC 2 Type II certification, MFA on all external systems, EDR on 100% of endpoints, 24x7 SOC (outsourced), immutable cloud backups with 4-hour RTO tested annually, privileged access management (PAM) deployed, email gateway with sandbox detonation, annual pen test by a Big 4 firm, and cyber incident response plan tested via tabletop in the last 12 months. Frame these controls in the language underwriters look for, emphasizing the controls that most reduce ransomware frequency and severity."

Board-Ready Cyber Risk Reporting

The SEC's 2023 cybersecurity disclosure rules require material cyber incidents to be disclosed in 8-K filings within 4 business days, and annual disclosure of material cyber risks and governance in the 10-K. Boards now need cyber risk information in the same format they receive financial risk information — probabilistic, financially quantified, and material-threshold assessed. Claude bridges the gap between CISO language and CFO/board language.

• "Convert the following CISO quarterly security report into a board-ready risk summary. The CISO report says: 'We patched 847 critical CVEs this quarter. Mean time to patch critical vulnerabilities improved from 18 days to 11 days. Phishing simulation click rate is 8.2%, down from 11.3%. We had two security incidents: one credential stuffing attempt (blocked) and one ransomware alert (isolated and contained). No data was exfiltrated.' Translate this into: (1) financial risk reduced (ALE improvement from the patching cadence improvement), (2) residual exposure based on current metrics, (3) trend vs. last quarter, (4) top 2 remaining risks in dollar terms, (5) management's recommendation. Maximum 1 page, board language."
• "Draft the cybersecurity risk disclosure section for our annual 10-K under the SEC's 2023 cybersecurity rules. We are a publicly traded asset manager ($8.2B AUM). Material cyber risks: (1) ransomware targeting fund NAV calculation systems could delay daily NAV publication, causing redemption rights issues, (2) data breach of investor PII (18,500 investors) would trigger SEC notification, CCPA obligations, and reputational harm. Governance: Board Risk Committee oversees cyber risk quarterly; CISO reports to CTO and directly to the committee. We had no material cyber incidents in the past fiscal year. Draft the 10-K disclosure in the format the SEC guidance suggests."

Third-Party and Supply Chain Cyber Risk

Financial services firms are heavily regulated on third-party risk (OCC guidance, DORA Article 25, NYDFS 500.11). Quantifying third-party cyber risk in FAIR terms enables prioritized vendor risk management — allocate due diligence effort where the financial exposure is highest, not where the vendor is biggest.

• "I have 15 critical vendors. Help me build a FAIR-based vendor risk prioritization model. For each vendor I can estimate: (1) business impact if they go down (revenue at risk per day), (2) probability of a significant incident at this vendor in the next year (based on their security ratings and industry data), (3) data shared (PII records count, financial data sensitivity). Build a scoring model that outputs a ranked list by expected annual financial exposure. Use the formula: Exposure = P(incident) × (business interruption cost + data breach cost). Show the top 5 vendors by exposure and the control questions I should ask them in my next due diligence review."

Where to Start

For most risk and finance teams new to FAIR, the entry point is a single high-priority scenario — typically ransomware against core systems. Use the prompt templates above to build your first FAIR analysis. The output gives you two immediate deliverables: a board risk report in financial language, and an input to your cyber insurance renewal conversation. Once you've run one FAIR scenario, the methodology is repeatable across your entire risk register. The Risk Management templates on ClaudeFinanceLab include additional cyber risk quantification frameworks.