The candidates who stall on insurance cases usually know the word "combined ratio." They recite it, then build a generic profitability tree that could belong to a snack brand. What the scoring sheet rewards is whether you treat the insurer as a machine that prices risk, holds float, and leaks money in claims — and whether your recommendation still works after retention moves.
This piece is written from the interviewer's side. You will leave with the three ratios that decode a P&C P&L, the capital and float constraints that sit behind growth cases, and one fully worked claims-leakage mini-case you can reproduce on a blank page. It is not a tour of every insurance product line; financial-services and broker cases already cover adjacent ground.
What the interviewer is actually scoring
An insurance prompt is still a case. Structure, math hygiene, judgment, and a clear recommendation still dominate the sheet. Industry vocabulary is a filter, not the grade.
I stop listening when a candidate says "we should improve underwriting" without naming which ratio moves, by how many points, and what happens to policies in force. I lean in when they ask, in the first two minutes, whether this is personal auto or commercial property, net or direct premium, and whether the objective is calendar-year profit or growth under a combined-ratio guardrail.
You do not need an actuarial background. You do need to sound like someone who has read a statutory income statement once.
The three ratios that run every P&C case
| Ratio | Usual formula | Interviewer translation |
|---|---|---|
| Loss ratio | Losses and loss-adjustment expenses / premiums earned | How much of each premium dollar is claims |
| Expense ratio | Underwriting expenses / premiums written (or earned; ask which) | Cost to acquire and run the book |
| Combined ratio | Loss ratio + expense ratio (+ policyholder dividends if material) | Underwriting profit if under 100 |
A combined ratio under 100 means underwriting earns money before investment income. Above 100, the book loses money on risk-bearing and needs float returns — or rate action — to stay whole.
Industry context keeps you honest. Industry analysts compiling statutory blanks put the 2024 U.S. P&C combined ratio near 96.5 — the best reading in more than a decade — with personal and commercial lines both under 100. That is the backdrop interviewers expect you to treat as real, not decorative.
Carriers that price tightly look different. Progressive's 2024 annual report to shareholders reports $70.8 billion of net premiums earned and $2.8 billion of investment income; management described a companywide combined ratio of 88.8 for the year. Use those figures as calibration, not as a case fact dump.
Float is the second P&L — and capital is the brake
Premiums arrive before claims leave. The money in between is float. Invest it well and an insurer can tolerate a thin underwriting result; invest it poorly and a 98 combined ratio still burns cash on a bad market year.
Berkshire Hathaway's 2024 shareholder letter puts the idea in public language: float at year-end 2024 was about $171 billion, up from $46 billion two decades earlier, with the prospect of that float being "costless" only if underwriting stays disciplined. In a case, always ask whether investment yield moved, or whether float itself shrank because the book ran off.
Growth is not free. U.S. regulators use risk-based capital (RBC) so surplus scales with underwriting, asset, credit, and related risks; state-published P&C RBC instructions walk through the statutory formula carriers file each year. Progressive's Form 10-K notes that written premium is often constrained relative to statutory surplus — historically framed around roughly a 3-to-1 premiums-to-surplus rule of thumb for many P&C books — and that NAIC RBC sits on top of that. If the prompt is "grow 20% next year," the follow-up that earns points is: do we have surplus and RBC headroom, or are we buying growth that forces a capital raise?
Retention belongs in the same breath as price. A rate filing that "fixes" the loss ratio but drops renewals 10 points can shrink float, scramble the expense ratio, and leave you with adverse selection in the book that stays.
Ned's rule. Never recommend a rate hike or a claims "efficiency" program without stating the expected combined-ratio delta and the retention (or volume) delta in the same sentence. One without the other is half an answer.
Case types that show up, ranked by how often I see them
| Prompt shape | What they want you to isolate | Common miss |
|---|---|---|
| Profitability / margin squeeze | Loss vs. expense vs. investment income | Ignoring float entirely |
| Pricing / rate adequacy | Loss-cost inflation vs. rate vs. retention | Treating price as free |
| Claims / leakage / LAE | Severity, frequency, recoveries, vendor spend | Calling everything "fraud" |
| Growth / new state / new product | Premises, capital, reinsurance, local loss costs | Sizing premium with no loss ratio |
| M&A / carve-out | Book quality, reserve adequacy, capital | Multiple of premium with no CR |
Claims leakage is under-taught on prep sites and over-used in real operations work. Leakage is money that left the loss and LAE line that should not have: missed subrogation, overpaid vendors, soft fraud, duplicate payments, weak litigation management. It is not the same as "bad weather." Weather is frequency and severity. Leakage is process.
Worked mini-case: Cedarline Mutual's claims-leakage decision
Cedarline Mutual is an invented regional personal-auto writer. Numbers are consistent but fictional. The CEO asks: invest in a claims-leakage unit, or push a mid-year rate increase?
Base year (current)
| Line | Amount |
|---|---|
| Net premiums earned | $1,000M |
| Losses and LAE | $780M |
| Underwriting expenses | $240M |
| Underwriting result | -$20M |
| Average float | $600M |
| Investment yield | 3.5% |
| Investment income | $21M |
| Pretax operating result | +$1M |
Ratios: loss 78%, expense 24%, combined 102%. Policy retention on the renewing book is 88%.
An internal audit estimates $45M of annual leakage inside the $780M loss and LAE line — mostly missed subrogation and body-shop overbilling, not catastrophe. Two options:
Option A — Leakage unit. Spend $12M per year (adds to expense). Recover $30M of the $45M leakage (reduces losses).
Option B — 5% rate increase on the renewing book, with retention expected to fall from 88% to 80%. Assume the non-renewing 8 points of the book leave with average loss experience (no heroic adverse-selection haircut in the first pass; flag it as a risk).
Option A math
New losses and LAE: $780M − $30M = $750M
New underwriting expenses: $240M + $12M = $252M
Premiums earned: still $1,000M (no price move)
| Metric | Base | Option A |
|---|---|---|
| Loss ratio | 78.0% | 75.0% |
| Expense ratio | 24.0% | 25.2% |
| Combined ratio | 102.0% | 100.2% |
| Underwriting result | -$20M | -$2M |
| Investment income | $21M | $21M |
| Pretax | +$1M | +$19M |
Net of the $12M spend, you pick up $18M pretax versus base. Combined ratio improves 1.8 points even though the expense ratio worsens — because the loss-ratio improvement is larger. That swap is what interviewers want to hear out loud.
Option B math (first-pass)
Renewing share of the book: treat earned premium as if 88% was going to renew; after the hike, 80% renews at 1.05× rate.
Earned premium ≈ $1,000M × (0.80 / 0.88) × 1.05 ≈ $955M
Losses if the leavers were average: $780M × (0.80 / 0.88) ≈ $709M
Expenses: assume $20M of acquisition and servicing falls away with the lost volume → $220M
| Metric | Base | Option B |
|---|---|---|
| Premiums earned | $1,000M | $955M |
| Loss ratio | 78.0% | 74.2% |
| Expense ratio | 24.0% | 23.0% |
| Combined ratio | 102.0% | 97.2% |
| Underwriting result | -$20M | +$26M |
| Float (scales with book) | $600M | ~$573M |
| Investment income @ 3.5% | $21M | ~$20M |
| Pretax | +$1M | ~$46M |
On pure year-one P&L, the rate hike wins. That is not the end of the case.
What I want in the recommendation
State both numbers, then choose with criteria. My preferred close for Cedarline: do the leakage unit now, and stage the rate filing. Leakage recovery does not require a regulator filing, does not buy a retention war, and improves the combined ratio without shrinking float. Use the cleaner loss ratio as evidence in the rate filing six months later; you may then need a smaller hike and lose fewer good risks. Flag that Option B's first-pass math ignores adverse selection — the 8 points who leave may be better-than-average risks — so the true Option B combined ratio is worse than 97.2 if the stayers are worse.
If the interviewer pushes for one move only, take A when brand and regulator optics matter, B when surplus is tight and you need calendar-year underwriting profit fast. Say the trade-off in one breath.
How to open the first two minutes
- Confirm line of business, geography, and whether figures are net of reinsurance.
- Draw premium → loss ratio / expense ratio → combined → float / investment income → capital / retention.
- Ask for the last two years of combined ratio and retention before you invent drivers.
- Only then pick a deep dive: pricing, claims, distribution, or investment.
If you skip step 2 and jump to "digital transformation," you have told the interviewer you are casing insurance like a software company.
Practice this today
Take Cedarline's base table and rewrite Option A with a $20M program that recovers only $22M. Recalculate the combined ratio. Then run one timed structure drill and one math drill on CoachNed so the ratio arithmetic is automatic under pressure: start at /start (three typed turns, instant scores, no account needed) or open the live voice case at /interview. Math and structure drills live at /drills/math and /drills/structure. Everything is open for seven days with no card; then $120 for a recruiting season or $49 a month.
CoachNed is not affiliated with McKinsey, BCG, Bain, Deloitte, or any insurer named above.
Frequently asked questions
Do I need insurance experience to pass an insurance case interview?
No. Interviewers expect clean structure and ratio math, not a Series license. What they punish is bluffing jargon. Use loss ratio, expense ratio, combined ratio, float, and retention correctly, and say when you are estimating.
What is a good combined ratio in a case?
Context first. Industry aggregates around the high 90s in a strong year on NAIC data; some personal-auto writers target mid-90s. In the room, "under 100 means underwriting profit" is the rule that matters. Compare the client's combined ratio to its own history before you praise or panic.
How is an insurance case different from a banking case?
Banks live on net interest margin and credit risk. P&C insurers live on combined ratio and float. Both care about capital, but the operating ratios and the product language differ. Do not force a bank ROE tree onto an auto book.
Should I mention reinsurance in every insurance case?
A combined ratio under 100 means underwriting earns money before investment income. Above 100, the book loses money on risk-bearing and needs float returns — or rate action — to stay whole.
Mention it when the prompt involves catastrophe exposure, surplus strain, or a specialty line. For a simple personal-auto leakage case, a one-line check ("figures net of reinsurance?") is enough. Do not hide behind a reinsurance digression to avoid the math.?
Cedarline Mutual is an invented regional personal-auto writer. Numbers are consistent but fictional. The CEO asks: invest in a claims-leakage unit, or push a mid-year rate increase?
What insurance vocabulary should I memorize the night before?
Loss ratio, expense ratio, combined ratio, premiums written vs. earned, float, retention, LAE, and RBC or surplus as a growth constraint. That list beats a glossary of twenty product names you will not use.
Sources
- 2024 P/C Insurance Combined Ratio: Best in More Than a Decade (Carrier Management / S&P Global Market Intelligence) — Aggregate 2024 U.S. P&C combined ratio near 96.5 from statutory filings. Checked 2026-09-24.
- The Progressive Corporation 2024 Annual Report to Shareholders (SEC exhibit) — Net premiums earned, investment income, and companywide combined-ratio context. Checked 2026-09-24.
- Progressive Corporation Form 10-K for the year ended December 31, 2024 — Statutory surplus, premiums-to-surplus framing, and RBC discussion. Checked 2026-09-24.
- Berkshire Hathaway 2024 Shareholder Letter — Public description of insurance float (~$171 billion at year-end 2024) and underwriting discipline. Checked 2026-09-24.
- 2024 Property/Casualty Risk-Based Capital Forecasting and Instructions (Indiana DOI / NAIC formula) — Statutory RBC formula that constrains growth cases. Checked 2026-09-24.