Present a reserve analysis to management, investors, or regulators, explaining what changed since the last estimate and why.

Every quarter the reserve number moves, and someone in the room asks why. Your job is to walk them from the last estimate to the new one, with every dollar of change tagged to a named cause.

Start with the accounting spine. Ultimate loss equals paid to date plus the reserve still held. Over a period, you pay claims and you may revise the ultimate. The reserve at period end follows directly.

$$R_{\text{current}} = R_{\text{prior}} - P_{\text{period}} + \Delta U$$

Here $\Delta U$ is the new ultimate minus the prior ultimate. That single term, $\Delta U$, is prior-year development. It is the heart of the "why," because payments were always expected; the revision was not.

KEY: Calendar-year incurred claims equal paid claims plus the change in total reserves: case outstanding plus incurred but not reported (IBNR). Paying a claim that was already reserved raises paid and lowers the reserve by the same amount, so on the prior accident years only $\Delta U$, the re-estimate of the ultimate, reaches calendar-year incurred.

Common mistakes

• Calling payments a "change." Paying $18,000,000 that was already reserved is not development; it swaps reserve for cash. On the prior years, only the re-estimate of the ultimate moves calendar-year incurred.
• Confusing total reserve growth with development. A $7,000,000 rise driven mostly by a new accident year is not $7 million of adverse development. Development was $3,000,000.
• Skipping actual-versus-expected. Changing the ultimate without showing the emergence gap leaves the audience no evidence. The $200,000 overage is what justifies the strengthening.

Bottom line

• A reserve analysis reconciles the prior ultimate estimate to the current one, attributing every dollar of change to a named cause.
• The roll-forward identity: current reserve equals prior reserve minus paid during the period plus the change in the ultimate loss estimate.
• Prior-year development is favorable when the estimate falls, adverse when it rises; it flows straight through calendar-year income.
• Actual-versus-expected emergence tests whether reported or paid losses came in above or below what the prior estimate implied.

Exam shortcut

Development always equals current ultimate minus prior ultimate. Positive is adverse and cuts income; negative is favorable and lifts it. Compute this before anything else the question asks. To find the current reserve fast, use prior reserve minus payments plus development. If the problem gives you paid-to-date and ultimates instead, just take current ultimate minus cumulative paid.

The full lesson (about 1,828 words, 12 min read) adds 2 worked examples, all 5 common mistakes, a self-check, free in the app.

Learning objectives

• B18

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