709,715 Extrapolated Custody for Bitcoin

Here’s the best current guesstimate based on on-chain analytics (primarily from Arkham Intelligence), public transfers reported in late 2025, and consistent patterns:

– **Majority appears under Fidelity Digital Assets / Fidelity Custody** (the dominant share now).  

  Strategy executed large transfers throughout late 2025 (e.g., ~58,390 BTC worth ~$5.1B in November 2025, plus additional ~11,642 BTC in early December 2025), moving coins from Coinbase to Fidelity. By late 2025, reports showed ~165,000–177,000 BTC explicitly sent to Fidelity. Given continued accumulation and no major reported reversals, analysts estimate Fidelity now custodies the **largest portion** (likely 40–60%+ of the total stack, potentially 300,000–450,000+ BTC). Fidelity uses an **omnibus custody model** (client assets are pooled/mixed in shared cold storage addresses), so individual client attribution becomes harder on-chain once deposited—much of Strategy’s BTC now shows up labeled under “Fidelity Custody” rather than a distinct Strategy entity.

– **Significant remaining portion still with Coinbase** (Coinbase Custody / Coinbase Prime).  

  Earlier holdings (pre-2025 diversification) were heavily Coinbase-based (hundreds of thousands of BTC in segregated wallets). Even after the big moves to Fidelity, a substantial amount (~200,000–300,000+ BTC) likely remains there, including segregated cold storage addresses that Arkham has historically tagged to Strategy.

– **Possibly smaller allocations elsewhere** (Anchorage Digital, others).  

  Strategy has appeared at events with Anchorage reps discussing custody, and their Bitcoin-for-Corporations materials reference multiple custodians (Coinbase Custody, Anchorage, Fidelity). No massive transfers to Anchorage have been publicly flagged recently, so any allocation there is probably minor.

– **No meaningful self-custody / cold wallets under direct company control** that are publicly known or tagged.  

  Michael Saylor and the company have consistently refused to publish wallet addresses, sign messages, or do traditional Proof-of-Reserves (citing security risks to the stack, custodians, and investors). Arkham Intelligence reverse-engineered and tagged ~87–92% of the holdings back in mid-2025 (mix of segregated Coinbase addresses + Fidelity omnibus inflows), but no new major self-custody revelation has occurred.

In summary:  

Rough split guess for the current ~709,715 BTC:  

– ~45–60%+ in **Fidelity Custody** (omnibus cold storage)  

– ~30–45% in **Coinbase Custody/Prime** (segregated + possibly some omnibus)  

– Balance scattered across 1–2 other qualified custodians or legacy setups