How does the expected return on plan assets assumption affect pension expense, and what should analysts watch for?

The expected return on plan assets (EROA) is one of the most subjective inputs in pension accounting under US GAAP. It has a direct, dollar-for-dollar impact on reported pension expense and, therefore, on net income.

How EROA Affects Pension Expense (US GAAP — ASC 715):

Pension expense components:

1. Service cost (+)
2. Interest cost (+) = Discount rate × Beginning PBO
3. Expected return on plan assets (−) = EROA × Beginning fair value of plan assets
4. Amortization of prior service cost (+/−)
5. Amortization of net actuarial gains/losses (+/−)

The expected return is a credit that reduces pension expense. A higher EROA assumption = lower pension expense = higher reported income.

Critical Point: Under US GAAP, the expected return (not the actual return) flows through the income statement. The difference between expected and actual returns is deferred in OCI as an actuarial gain/loss.

Under IFRS (IAS 19 revised), there is NO expected return assumption — the income statement uses the net interest approach (discount rate × net pension liability/asset). This eliminates management's discretion on the return assumption.

Worked Example — Bradfield Corp:

Difference in reported income (pre-tax): $15M − $2.5M = $12,500,000

By using an aggressive 8.5% EROA vs. a conservative 6.0%, Bradfield increases pre-tax income by $12.5 million — purely through an assumption.

Red Flags for Analysts:

1. EROA significantly above peer average — compare the assumption to companies with similar plan asset allocations
2. EROA unchanged despite asset allocation shifts — if the company moved from equities to bonds but maintained a high EROA
3. EROA above historical actual returns — if the plan consistently earns less than expected, the assumption is too aggressive
4. EROA disconnected from discount rate — typically, EROA should be somewhat above the discount rate (reflecting equity risk premium), but a very wide spread warrants scrutiny

Typical EROA Ranges by Asset Allocation:

Key Exam Points:

1. Under US GAAP, EROA directly reduces pension expense — higher assumption = higher earnings.
2. Under IFRS, the EROA concept does not exist — the discount rate is applied to the net pension position.
3. EROA is a management choice, not a market observation — this makes it a key tool for earnings management.
4. Analysts should compare EROA to actual returns over time and to peer assumptions.

Explore more pension analysis techniques in our CFA Level II question bank.