Authorize a 401(k) plan termination

Last updated Jun 14, 2026

Board resolution, blackout notice, IRS Form 5310, distributions to participants.

Trigger

You're terminating a 401(k) — typically as a precondition to an acquihire or dissolution.

Call sequence

1. Record termination intent on the linked plan

POST /v1/benefit_plans/{plan}/terminate

2. Issue blackout notice (ERISA §101(i))

POST /v1/documents  { template: 'tpl_blackout_v2' }

3. File IRS Form 5310 via sub-agent

POST /v1/sub_agent_sessions  { kind: 'irs_5310' }

4. Run distributions

POST /v1/benefit_plans/{plan}/distribute

Idempotency

Termination idempotent on `(entity, plan)`.

Webhooks

Errors

Post-dissolution plan administrator

When the entity is winding down, the record-keeper still needs a human contact through the §278 wind-up tail (the IRS may take 6–18 months to issue the Form 5310 determination letter; participant distributions can take longer; the plan trust persists past entity dissolution).

Matter records this designation on the dissolved entity's post_dissolution_responsible_persons[]. The named individual is the record-keeper's contact; the record-keeper administers the trust.

POST /v1/entities/ent_Nq3KcAbc/post_dissolution_responsible_persons
{
  "kind": "plan_administrator",
  "stakeholder_id": "stk_founder",
  "benefit_plan_id": "bp_5nMpQrSt",
  "designation_resolution_id": "res_LqGcSdRb"
}

Replacement requires a new Resolution of kind benefit_plan_administrator_designation.

Compliance calendar obligations

Filing.type: irs_form_5310 and irs_form_5500_final appear on the Compliance calendar with their statutory deadlines. The record-keeper files the actual returns; Matter tracks the obligation cadence and flips the Filing's status to accepted on the record-keeper's webhook acknowledgement.

{
  "object": "compliance",
  "filings_due": [
    {
      "type": "irs_form_5310",
      "due_at": "2026-12-31",
      "responsible_party": "record_keeper",
      "filing_id": null
    },
    {
      "type": "irs_form_5500_final",
      "due_at": "2027-07-31",
      "responsible_party": "record_keeper",
      "filing_id": null
    }
  ]
}

What this recipe does NOT cover

These belong to the record-keeper, not Matter:

• Form 5310 content. The record-keeper drafts and files; Matter only surfaces the obligation.
• Form 5500-final content. Same.
• Participant distributions. The record-keeper distributes account balances, handles rollover elections, applies IRS withholding, and issues Form 1099-R per participant.
• Trust administration during wind-up. The record-keeper administers the trust until all participant balances are distributed.
• COBRA continuation tracking for any associated medical plans. See the payroll-and-benefits handoff — the benefits administrator runs this; Matter generates the qualifying-event notice (a statutory legal Document).

If a downstream concern looks like Matter's role but isn't on this page, read the handoff convention page first.

Related

• Payroll and benefits handoff — the canonical boundary between Matter's role and the provider's.
• Dissolve an entity — the broader dissolution flow this slots into.
• Run a board consent — the authorising Resolution flow.