Defined Benefit (Pension) · DOL Form 5500 · 2023

Northwestern Corporation Pension Plan

Data updated 2026-08-25

$350M
Total assets Above avg plan size
387
Participants Below avg headcount
97th
Percentile by assets National rank
$904,895
Avg per participant High balance/head
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Official DOL plan name: Northwestern Energy Mt Pension Plan · Sponsored by Northwestern Corporation · Montana · Utilities

$350M in assets, 387 participants

Northwestern Corporation's Northwestern Energy Mt Pension Plan reported $350M in total assets and 387 participants in its 2023 DOL Form 5500 filing, ranking in the 97th percentile by assets among filed plans. Figures are as reported by the plan sponsor to the Department of Labor, not audited or endorsed by PlainRetire.

  • #562 in Utilities (721 peers)

Where Northwestern Energy Mt Pension Plan sits by assets

Northwestern Energy Mt Pension Plan sits in the top 5% of all filed plans by assets, $350M for 387 participants (~$904,895/participant), down 11.4% in 2023.

#562
in Utilities (721 peers)
-11.4%
assets change YoY
3.5×
vs typical plan assets (national mean)

The plan reported a net loss of $46M for the year, a single-year figure driven by markets and benefit payments, not a measure of plan health.

Northwestern Energy Mt Pension Plan's outsized position by total assets

Northwestern Energy Mt Pension Plan vs every filed plan by assets

End-of-year total assets · plan year 2023 · DOL Form 5500

$350,194,280 Top 3% higher than 97% of 127,068 filed plans

This plan $0 $2,050,000,000 every filed plan with reported assets, bucketed by value

Dashed line + filled bar = this entry, among filed plans.

Source U.S. Department of Labor Form 5500 filings (EBSA) · plan year 2023

Northwestern Energy Mt Pension Plan among mid-size filed plans by headcount

Plan-year 2023 Form 5500 filings with a reported participant count, partitioned by headcount band, not by assets. Northwestern Energy Mt Pension Plan sits mid-pack in the medium band (387 participants).

What changed between DOL Form 5500 filings

plan year 2022 → plan year 2023

  • Northwestern Energy Mt Pension Plan reported net income rose from -$149M in the plan year 2022 filing to -$46M in the plan year 2023 filing.
  • Northwestern Energy Mt Pension Plan reported participants fell from 451 in the plan year 2022 filing to 387 in the plan year 2023 filing.
  • Northwestern Energy Mt Pension Plan end-of-year assets fell from $395M in the plan year 2022 filing to $350M in the plan year 2023 filing.

See the national 2022→2023 release diff →

Form 5500 schedule snapshot

Filing strip 460172280 · Northwestern Corporation PY 2023 · Defined Benefit (Pension)

Northwestern Energy Mt Pension Plan · $350M · 387 · 97th

  • TYPE $350M
  • TYPE 387
  • TYPE 97th
  • TYPE Defined Benefit (Pension)
  • TYPE near Plumbers and Steamfitters Local 486 Pension Fund
  • TYPE ind #562

Stamps derive from this plan's Form 5500 line items (assets, participants, type, EIN, cohort placement) - not a quality rating of the sponsor. Read with Utilities retirement plans → · Plans in Montana →

Northwestern Energy Mt Pension Plan in the asset neighbourhood

Chicago Area Ib of T Pension Trust FundChicago Area Ib of T Pension…$351MNorthwestern Energy Mt Pension PlanNorthwestern Energy Mt Pensi…$350MPlumbers and Steamfitters Local 486 Pension FundPlumbers and Steamfitters Lo…$350MRetirement Plan of American Fidelity GroupRetirement Plan of American …$349MThe Adjustable Plan of the Unite Here RetirementThe Adjustable Plan of the U…$349M
End-of-year total assets ($M) among Northwestern Energy Mt Pension Plan and nearest nationwide Defined Benefit (Pension) peers. Source: DOL Form 5500 plan year 2023.

Scale-class filing particulars (2023)

Total Assets (Beginning of Year)$395M
Net Assets (End of Year)$349M
Net Income-$46M
Employer EIN460172280
Plan Effective Date1948-06-01
Filing StatusFILING RECEIVED

Sponsor Plan History (Northwestern Corporation)

Sponsor-wide plan assets over time

All Northwestern Corporation plans reported in each filing year

Latest sponsor-wide plan assets
$911M 6.581242375535956% vs 2022
2024 filing year
$840M$860M$880M$900M$920M 202220232024 $855M $911M ▲ +6.6%
Year Plans Participants Total Assets
2022 3 2,084 $855M
2023 3 2,047 $869M
2024 3 2,037 $911M

Nearby Defined Benefit (Pension) Plans in Montana

Peer Defined Benefit (Pension) plans, same state, same plan type, ranked by total assets.

Northwestern Energy Mt Pension Plan vs. nearby Defined Benefit (Pension) plans in Montana, assets vs. participants Scatter plot of 6 data points. 0100200300400500 -1000100200300400 Total assets ($M) Participants Northwestern Energy Mt Pension Plan, Total assets ($M): 350.19428 · Participants: 387Northwestern Energy Mt Pension PlanSt. Peter's Health Cashplus Retirement Plan, Total assets ($M): 56.808753 · Participants: 285St. Peter's Health Cashplus Retirement PlanNorthwestern Energy Sd/Ne Pension Plan, Total assets ($M): 55.71111 · Participants: 131Northwestern Energy Sd/Ne Pension PlanRetirement Plan for Employees of Northern Montana Hospital, Total assets ($M): 34.073428 · Participants: 111Retirement Plan for Employees of Northern Montana HospitalPension Plan for Employees of Advanced Silicon Materials, LLC, Total assets ($M): 28.641653 · Participants: 76Pension Plan for Employees of Advanced Silicon Materials, LLCAmerican Chemet Corporation Retirement Income Plan, Total assets ($M): 16.095512 · Participants: 51American Chemet Corporation Retirement Income Plan
Northwestern Energy Mt Pension Plan vs. nearby Defined Benefit (Pension) plans in Montana, assets vs. participants
Compare Northwestern Energy Mt Pension Plan side-by-side with 3 peers →

Northwestern Energy Mt Pension Plan's out-of-state Defined Benefit (Pension) peers by assets and headcount

Outside Montana, the nearest Defined Benefit (Pension) by assets is Plumbers and Steamfitters Local 486 Pension Fund in MD ($350M); by covered participants it is Unisys Pension Plan in PA (387 participants). Same-state nearby plans are listed separately above.

Closest by plan assets

Nearest other-state filings by tot_assets_eoy ($350M here).

Similar participant headcount

Nearest other-state filings by covered participants (387 participants); asset peers above are excluded.

DOL Form 5500 plan year 2023. Asset totals can differ widely at the same headcount; neither axis is a quality rating.

Frequently Asked Questions

How did Northwestern Energy Mt Pension Plan assets move in 2023? ▼
Northwestern Energy Mt Pension Plan pulled back noticeably - down 11.4% during 2023, from $395M to $350M. Reported net income was -$46M.
How have Northwestern Corporation plan assets changed over time? ▼
Across 3 plan years on file (2022-2024), Northwestern Corporation's sponsor-wide assets grew 6.6%, from $855M to $911M.
Where does Northwestern Energy Mt Pension Plan rank by assets among Form 5500 filers? ▼
Northwestern Energy Mt Pension Plan ranks in the 97th percentile by end-of-year assets among 127,072 plans that reported assets for plan year 2023 (in the top 5% of all filed plans by assets).
Which Defined Benefit (Pension) plans are similar in size to Northwestern Energy Mt Pension Plan? ▼
Among Defined Benefit (Pension) plans in other states, the closest by assets is Plumbers and Steamfitters Local 486 Pension Fund in MD ($350M, 1,522 participants).
Which Defined Benefit (Pension) plans cover a similar participant headcount to Northwestern Energy Mt Pension Plan? ▼
Among Defined Benefit (Pension) plans in other states, the closest by covered participants is Unisys Pension Plan in PA (387 participants, $1.7B in assets).

Source: U.S. Department of Labor, Employee Benefits Security Administration (EBSA), Form 5500 public disclosure dataset. Plan year 2023.

Source: DOL EFAST2 filing system (efast.dol.gov) - original filing retrieval by EIN 460172280.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from U.S. Department of Labor Form 5500 filings (EBSA). See our methodology for details.