How are actuarial gains and losses on defined benefit pensions treated in OCI, and when do they get amortized?

Question

AcadiFi · Accepted Answer

Pension actuarial gains and losses under US GAAP follow a deferred recognition approach that many candidates find counter-intuitive. Here is the complete framework.

**What Creates Actuarial Gains/Losses?**

They arise from:
- Changes in assumptions (discount rate, mortality, turnover, salary growth)
- Differences between expected and actual return on plan assets

Dunmore's case: the discount rate dropped, increasing the PBO by $45M. This is an actuarial **loss** (obligation grew unexpectedly).

**Initial Recognition**

Under US GAAP, actuarial gains and losses are recognized in **OCI** (not the income statement) in the period they arise.

- DR: OCI — Actuarial loss — $45M
- CR: Projected Benefit Obligation — $45M

This avoids income statement volatility but accumulates in AOCI on the balance sheet.

**The Corridor Amortization Method**

US GAAP uses the corridor approach to determine when accumulated actuarial gains/losses begin flowing to pension expense:

**Corridor = 10% x MAX(PBO, Fair value of plan assets) at beginning of year**

Only the **excess** above the corridor is amortized, and amortization uses the straight-line method over the average remaining service period of employees.

**Dunmore Example:**

Assume at the beginning of Year 2:
- Accumulated net actuarial losses in AOCI: $120M
- PBO: $800M
- Plan assets fair value: $700M
- Average remaining service period: 15 years

Corridor = 10% x MAX($800M, $700M) = 10% x $800M = **$80M**

Excess = $120M - $80M = **$40M**

Amortization in Year 2 = $40M / 15 years = **$2.67M**

This $2.67M is included in pension expense on the income statement and reduces the accumulated loss in AOCI.

```mermaid
flowchart TD
    A["Actuarial Gain/Loss Arises"] --> B["Recognized in OCI"]
    B --> C["Accumulates in AOCI"]
    C --> D{"Accumulated Amount >
10% x MAX(PBO, Plan Assets)?"}
    D -->|Yes| E["Amortize Excess over
Avg Service Period"]
    D -->|No| F["No Amortization
Stay in AOCI"]
    E --> G["Flows to Pension Expense
on Income Statement"]
```

**IFRS Difference**

Under IAS 19 (revised), actuarial gains and losses are recognized in OCI immediately and are **never** recycled to the income statement. There is no corridor method under IFRS. This is a critical GAAP vs. IFRS distinction.

| Feature | US GAAP | IFRS |
|---|---|---|
| Initial recognition | OCI | OCI |
| Corridor amortization | Yes — excess over 10% corridor | **No — never recycled** |
| Income statement impact | Eventually, through amortization | Never |

**Exam tip:** If the question asks for pension expense under US GAAP, check whether accumulated OCI exceeds the corridor — that amortization component is easy to miss.

Explore our pension accounting modules in the CFA Level II FRA course.

How are actuarial gains and losses on defined benefit pensions treated in OCI, and when do they get amortized?

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Related Questions

Practice Questions

Feature	US GAAP	IFRS
Initial recognition	OCI	OCI
Corridor amortization	Yes — excess over 10% corridor	No — never recycled
Income statement impact	Eventually, through amortization	Never