Actuarial, Accounting, Regulation — What a Future Promise Is Worth Today

In one line

Insurance accounting is the question of "how much to book now for money to be paid in the future," and three layers — policy reserves (cost basis), IFRS 17 liabilities (current-value basis), and K-ICS solvency (capital) — look at the same contract as different numbers — and the Insurance Business Act and personal information regulation add IT requirements on top.

Why this knowledge is needed

The requirements for an insurer's closing system contain phrases like "reserve calculation batch," "IFRS 17 engine integration," "K-ICS calculation data mart," and "sensitive information encryption." If you do not know the backbone of these words the actuarial team uses, you cannot understand why there are so many data items, why the liability of the same contract differs from screen to screen, or why the system runs all night at every close.

Policy reserves — liabilities booked at cost

An insurer keeps the promises of decades from now with the premiums it receives today. The money set aside now for those promises is the policy reserve. The premium reserve of term insurance is "the present value of benefits to be paid in the future − the present value of net premiums to be received in the future." In the early period of enrollment, there are many premiums left to receive, so it is small, and it grows over time. The assumptions used in the calculation are the risk rates and assumed interest rate at the time of enrollment. That is why it is called the cost basis.

Reserves have other components too. The claims reserve for claims not yet paid (case reserves and IBNR), the unearned premium reserve for premiums whose period has not yet passed, and so on. The closing batch calculates these components per contract and coverage and adds them up.

IFRS 17 — liabilities booked at current value

IFRS 17, applied since 2023, evaluates liabilities with current assumptions.

BEL   Best estimate liability. Future cash flows (benefits + expenses − premiums) valued at current discount rates.
RA    Risk adjustment. Compensation for uncertainty in those cash flows. The insurer chooses the method.
CSM   Contractual service margin. Unearned profit left after BEL + RA. Held as a liability, released as profit over the coverage period.

The CSM is the key. It prevents recognizing all the profit the moment a contract is sold and releases it each period only as much as service has been provided. Conversely, if BEL + RA is larger than the premium, the CSM is 0 and the difference immediately becomes a loss as a loss component. A closing system needs a roll-forward that carries the CSM balance per contract group, and the CSM is adjusted every time assumptions change.

K-ICS — soundness viewed through capital

The solvency regime looks at whether the whole company can withstand extreme losses. Insurance, market, credit, and operational risks are each converted to capital requirements and combined by applying correlation coefficients under the assumption that the risks do not all hit at the same time. Available capital ÷ required capital is the solvency ratio, and the legal minimum is 100%, with the supervisory authority recommending a higher level (the specific figures differ by time and regime). For IT, this comes down as "a data mart with assets, liabilities, and contracts broken down by risk factor."

The Insurance Business Act and personal information

The Insurance Business Act deals with product filing, management of basic documents (terms and conditions, the business method statement, and the calculation method statement), solicitation procedures, asset management limits, and accounting standards. From an IT point of view, what matters is the calculation method statement — how premiums and reserves are calculated is in this document, and the system must implement this document as is. On the personal information side, the key point is that the information insurance handles is sensitive information (health, illness) and unique identification information (resident registration numbers). The Personal Information Protection Act requires separate consent and safeguards such as encryption for their processing, and the Credit Information Act applies overlappingly. Diagnosis certificates and medical records in claim documents belong to the most sensitive axis, so access permissions, masking, and retention periods must be in the requirements.

Problems that arise when moving actuarial calculations into a system

IFRS 17 and K-ICS are accounting standards, but in practice they come down as requirements of a calculation system. There are three ways these requirements differ from ordinary business systems.

The volume of calculation is large, and the calculation has to be repeated. For each contract you generate future cash flows for decades, and run them through multiple scenarios. With millions of contracts, batch time can be measured in days. So you need from the start a structure that stores how far the calculation has gone and can restart from the middle. If it fails after running everything, you cannot rerun from the beginning.

The same input must give the same answer. In an audit, the demand "show how this number was derived" comes. For that, you must store the assumptions, rate table version, and code version used in the calculation along with the result. A system that stores only results cannot reproduce that number months later.

Estimates change later. If assumptions change after the accounting close, it must be decided whether to reflect from that point on or to recompute the past. On the system side, this shows up as the rule "lock the finalized period." Without a lock, the numbers of a closed quarter quietly change, and you discover that fact in the external audit.

Developers do not need to know all of actuarial science, but they must ask three things. What is the reference date of this number, what assumptions were used, and does recomputing give the same value? If these three have answers, the rest is for the actuary in charge.

Performance usually comes from input and output. If you store per-contract cash flows in columnar form rather than rows and compress them, it shrinks a lot. Often the time to read and write the results takes up most of the batch rather than the calculation itself.

What really matters in practice

First, the same contract has different numbers in the three layers. That the cost-basis reserve and the IFRS 17 liability differ is not an error but because the assumptions differ. When reconciling, do not mix the layers.

Second, assumptions are data and have versions. The risk tables, discount rate curves, and expense assumptions are finalized at each closing, and which assumptions were used in which close is the condition for reproduction.

Third, touch sensitive information to a minimum. Reserves and loss ratios can be calculated without diagnosis names. First ask whether diagnosis codes are really needed in the analysis mart, and if needed, build masking and access control into the design.

In the next lab, you will calculate policy reserves for 5 contracts, pull out BEL, RA, and CSM at the current discount rate, and build even the solvency ratio from company figures in one go.