EDISON INTERNATIONAL

Nature of Estimate Required. Authoritative accounting guidance requires companies to recognize the overfunded or underfunded status of defined benefit pension and other postretirement plans as assets and liabilities in the balance sheet; the assets and/or liabilities are normally offset through other comprehensive income (loss). In accordance with authoritative guidance for rate-regulated enterprises, regulatory assets and liabilities are recorded instead of charges and credits to other comprehensive income (loss) for its postretirement benefit plans that are recoverable in utility rates. Edison International and SCE have a fiscal year-end measurement date for all of their postretirement plans.

Key Assumptions of Approach Used. Pension and other postretirement benefit obligations and the related effects on results of operations are calculated using actuarial models. Two critical assumptions, discount rate and expected return on assets, are important elements of plan expense, and the discount rate is important to liability measurement. Other assumptions, which require management judgment, include the rate of compensation increases, and rates of retirement, turnover and termination. Additionally, health care cost trend rates are critical assumptions for postretirement health care plans. These critical assumptions are evaluated periodically and updated to reflect actual experience, as appropriate.

As of December 31, 2024, Edison International's and SCE's pension plans had a $3.6 billion and $3.3 billion projected benefit obligation, respectively, and total 2024 expense for these plans was $27 million and $24 million, respectively. As of December 31, 2024, the accumulated benefit obligation for Edison International's and SCE's PBOP plans were $741 million and $737 million, respectively, and there were no expenses for Edison International's and SCE's PBOP plans for 2024. The majority of annual contributions made to SCE's pension and PBOP plan are anticipated to be recovered through CPUC-approved regulatory mechanisms and are expected to be, at a minimum, equal to the related annual expense.

Pension expense is recorded for SCE based on the amount funded to the trusts, as calculated using an actuarial method required for ratemaking purposes, in which the impact of market volatility on plan assets is recognized in earnings on a more gradual basis. Any difference between pension expense calculated in accordance with ratemaking methods and pension expense calculated in accordance with authoritative accounting guidance for pension is accumulated as a regulatory asset or liability, and is expected, over time, to be recovered from or returned to customers. As of December 31, 2024, this cumulative difference amounted to $132 million, meaning that the ratemaking method has recognized less in expense than the accounting method since implementation of authoritative guidance for employers' accounting for pensions in 1987, which was offset by a regulatory liability for the current funding level of SCE's pension plan.

Edison International and SCE used the following critical assumptions to determine expense for pension and PBOP for 2024:

*Not applicable to pension plans.

1 The discount rate enables Edison International and SCE to state expected future cash flows at a present value on the measurement date. Edison International and SCE select its discount rate by performing a yield curve analysis. This analysis determines the equivalent discount rate on projected cash flows by matching the timing and amount of expected future benefit payments to the corresponding yields from the Willis Towers Watson RATE: Link 10th – 90th percentile yield curve model on the measurement date.

2 To determine the expected long-term rate of return on pension plan assets, current and expected asset allocations are considered, as well as historical and expected returns on plan assets. A portion of PBOP trusts asset returns are subject to taxation, so the 5% rate of return on plan assets above is determined on an after-tax basis. Actual time-weighted, annualized returns on the pension plan assets were 5.6%, 5.2% and 6.6% for the one-year, five-year and ten-year periods ended December 31, 2024, respectively. Actual time-weighted, annualized returns on the PBOP plan assets were 3.5%, 1.8% and 4.3% over these same periods. Accounting principles provide that differences between expected and actual returns are recognized over the average future service of employees.

3 The health care cost trend rate gradually declines to 5.00% for 2029 and beyond.

As of December 31, 2024, Edison International and SCE had unrecognized net pension gains of $138 million and $120 million, respectively, and unrecognized PBOP gains of $1.5 billion. The unrecognized pension and PBOP gains primarily consisted of the cumulative impact of the increased discount rates on the respective benefit obligations and the cumulative difference between the expected and actual rate of return on plan assets. Of these deferred gains, $133 million of SCE's pension gains and $1.5 billion of SCE's PBOP gains are recorded as regulatory liabilities, respectively, and are expected to be amortized to expense over the expected future service of the employees (subject to regulatory adjustment) or refunded to ratepayers at the termination or completion of the plan.

Edison International's and SCE's pension and PBOP plans are subject to limits established for federal tax deductibility. SCE funds its pension and PBOP plans in accordance with amounts allowed by the CPUC. Executive pension plans have no plan assets.

Effect if Different Assumptions Used. Changes in the estimated costs or timing of pension and other postretirement benefit obligations, or the assumptions and judgments used by management underlying these estimates, could have a material effect on the recorded expenses and liabilities.

The following table summarizes the increase or decrease to projected benefit obligation for pension and the accumulated benefit obligation for PBOP if the discount rate were changed while leaving all other assumptions constant:

A one percentage point increase in the expected rate of return on pension plan assets would decrease Edison International's and SCE's current year expense by $35 million and $33 million, respectively, and a one percentage point increase in the expected rate of return on PBOP plan assets would decrease both Edison International's and SCE's current year expense by $23 million.