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EntityWire/Indiana business entity search →/MIDCONTINENT INDEPENDENT SYSTEM OPERATOR INC

Tax-exempt organization

MIDCONTINENT INDEPENDENT SYSTEM OPERATOR INC

MIDCONTINENT INDEPENDENT SYSTEM OPERATOR INC's Employer Identification Number (EIN) is 43-1827033.

At a glance

EIN
43-1827033 · 431827033
Legal name
MIDCONTINENT INDEPENDENT SYSTEM OPERATOR INC
Also filed as
MISO
Address on file
720 CITY CENTER DR, CARMEL, IN 46032-3826
Records show
Tax-exempt organization; employer with a benefit plan
Latest record
2026-09

Benefit plans

DOL Form 5500 filings (EFAST2) · records as of 2025-08-28

Benefit plan 1, 2024 filing
MISO EMPLOYEES' RETIREMENT SAVINGS PLAN
Source: DOL 5500 · as of 2025-08-28
Participants (start of year)
1,384
Source: DOL 5500 · as of 2025-08-28
Plan features
Profit-sharing; ERISA 404(c) plan; Participant-directed; 401(k) feature; 401(m) matching; Pension plan with defined contribution
Source: DOL 5500 · as of 2025-08-28
Plan type
Single-employer plan
Source: DOL 5500 · as of 2025-08-28
Business code (NAICS)
221100
Source: DOL 5500 · as of 2025-08-28
Benefit plan 510, 2024 filing
MIDCONTINENT INDEPENDENT SYSTEMS OPERATOR, INC. EMPLOYEE BENEFIT PLAN
Source: DOL 5500 · as of 2025-07-29
Participants (start of year)
1,070
Source: DOL 5500 · as of 2025-07-29

IRS exempt organization record

IRS Exempt Organizations Business Master File · records as of 2026-09

Tax-exempt status
501(c)(4) social welfare
Source: IRS · as of 2026-09
Deductibility
Contributions are not deductible
Source: IRS · as of 2026-09
IRS ruling date
2001-01
Source: IRS · as of 2026-09
NTEE code
W80
Source: IRS · as of 2026-09
Latest tax period on file
2024-12
Source: IRS · as of 2026-09
Revenue (latest 990)
$616,078,935
Source: IRS · as of 2026-09
Assets (latest 990)
$3,354,403,000
Source: IRS · as of 2026-09

What this record is

Public filings that carry this EIN (DOL Form 5500 filings (EFAST2), DOL Form 5500-SF filings (EFAST2) and IRS Exempt Organizations Business Master File), shown as filed. Nothing is scraped from the IRS, and a public-record match is not IRS TIN validation.

What it is not

Registry status, formation date, and registered agent come from the Indiana Secretary of State, Business Services Division; see the Indiana business entity search.

If something is wrong

A name, address, or classification here is what the source published. To correct the source, file with it; to have this page removed, see corrections and removal.

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