---
schema_version: "secwatch.filing_event.v1"
accession: "0001213900-25-123286"
form_type: "8-K"
ticker: "ARKB"
cik: "0001869699"
company_name: "Ark 21Shares Bitcoin ETF"
filed_at: "2025-12-18T23:59:59+00:00"
generated_at: "2026-05-16T12:47:06.792479+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.35
calibrated_materiality_score: 0.35
confidence: "high"
source: SEC EDGAR
---

# ARK 21Shares Bitcoin ETF adds BitGo as custodian and Macquarie as AP with in-kind creation

## Summary
- Entered custodial services agreement with BitGo Trust Company to custody a portion of Trust's bitcoin starting Dec 12, 2025.
- Will allocate bitcoin among existing custodians (Coinbase, Anchorage, BitGo New York) and BitGo; allocation not disclosed.
- Sponsor bears transfer fees between custodians; on-chain transfers subject to Bitcoin network risks.
- Entered authorized participant agreement with Macquarie Capital on Dec 16, 2025, allowing in-kind creation/redemption of baskets.
- Transaction fees for creation/redemption may apply unless waived by sponsor.

## SEC filing metadata
- accession: 0001213900-25-123286
- form_type: 8-K
- ticker: ARKB
- cik: 0001869699
- company_name: Ark 21Shares Bitcoin ETF
- filed_at: 2025-12-18T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.35
- calibrated_materiality_score: 0.35
- confidence: high
- sec_items: 1.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1869699/000121390025123286/0001213900-25-123286-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1869699/000121390025123286/ea0270186-8k_ark21share.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001213900-25-123286
- JSON: https://secwatch.observer/filing/0001213900-25-123286.json
- Plain text: https://secwatch.observer/filing/0001213900-25-123286.txt

## Key facts
- Material Agreements
  Ark 21Shares Bitcoin ETF entered into Authorized Participant Agreement with Macquarie Capital (USA) Inc. (effective 2025-12-16).
  - Action: entry
  - Counterparty: Macquarie Capital (USA) Inc.
  - Effective: 2025-12-16
  source text: On December 16, 2025, the Trust entered into a new authorized participant agreement (the “Authorized Participant Agreement”) with Macquarie Capital (USA) Inc. (“Macquarie”), pursuant to which Macquarie has agreed to act as an authorized participant of the Trust.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1869699/000121390025123286/0001213900-25-123286-index.htm
- Material Agreements
  Ark 21Shares Bitcoin ETF entered into Custodial Services Agreement with BitGo Trust Company, Inc. (effective 2025-12-12).
  - Action: entry
  - Counterparty: BitGo Trust Company, Inc.
  - Effective: 2025-12-12
  source text: On December 12, 2025, ARK 21Shares Bitcoin ETF (the “Trust”) entered into a new custodial services agreement (the “Custodial Services Agreement”) with BitGo Trust Company, Inc., a South Dakota trust company (“BitGo”).
  evidence_url: https://www.sec.gov/Archives/edgar/data/1869699/000121390025123286/0001213900-25-123286-index.htm

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.