TL;DR: Coinbase Prime dominates (~70% of public company BTC holdings), but centralized custody limits proof of reserves. BitGo offers multi-sig flexibility. Fidelity brings TradFi credibility. Unchained enables collaborative custody with full verification capability. Your custody choice directly affects your ability to prove holdings.
MicroStrategy trusts Coinbase with $60 billion in Bitcoin. Would you?
Corporate Bitcoin custody isn’t a checkbox decision. Your choice affects insurance, regulatory compliance, proof of reserves, and ultimately whether you can prove to shareholders that the Bitcoin is actually there.
We analyzed SEC filings from 50+ Bitcoin treasury companies to see which custodians they use and why. Here’s what we found.
Key Takeaways
| Custodian | Market Share | Best For | Proof of Reserves |
|---|---|---|---|
| Coinbase Prime | ~70% | Simplicity, liquidity | Limited (attestation only) |
| BitGo | ~15% | Multi-sig control | Good (client key access) |
| Fidelity | ~10% | TradFi credibility | Limited |
| Unchained | Growing | Proof verification | Excellent (client controls keys) |
Why Custody Matters for Corporate Bitcoin
Corporate custody is fundamentally different from personal custody. The stakes are higher: fiduciary duty, regulatory scrutiny, insurance requirements, and shareholder accountability.
Security Requirements
| Requirement | What It Means | Why It Matters |
|---|---|---|
| HSMs | Hardware Security Modules for key storage | Keys never touch internet-connected devices |
| Air-gapped signing | Signing happens on offline devices | Prevents remote attacks |
| Geographic distribution | Keys stored in multiple locations | Survives disasters |
| Multi-signature | Multiple keys required to move funds | No single point of failure |
| Approval workflows | Multiple people must approve transactions | Prevents insider theft |
Insurance and Liability
If Bitcoin is stolen, who’s liable? Custodians provide:
- Crime/theft insurance policies
- Errors & omissions coverage
- Clear liability frameworks
Without proper custody, directors could face personal liability.
Proof of Reserves Implications
Your custody choice affects your ability to provide proof:
| Custody Model | Key Control | Proof Capability |
|---|---|---|
| Self-custody | Company holds all keys | ✅ Can sign messages directly |
| Full custodial | Custodian holds all keys | ⚠️ Depends on custodian attestation |
| Collaborative | Shared (e.g., 2-of-3) | ✅ Client keys enable proof |
Critical question: Companies using custodians should ask: Can you provide cryptographic proof of our holdings? If not, reconsider. Learn more about proof of reserves for treasury companies.
Coinbase Prime (Institutional)
Coinbase Prime is the dominant custody solution for public Bitcoin treasury companies. Based on our SEC filing analysis, approximately 70% of public company Bitcoin is held through Coinbase.
Who Uses It
| Company | Holdings | Notes |
|---|---|---|
| MicroStrategy | ~$60B | Largest holder |
| Tesla | ~$1B | Remaining BTC position |
| Marathon Digital | Mining output | Plus purchased BTC |
Pros and Cons
| ✅ Pros | ❌ Cons |
|---|---|
| Largest, battle-tested custodian | Centralized (Coinbase controls keys) |
| $320M insurance policy | Limited proof of reserves capability |
| Integrated trading platform | Premium pricing |
| US-regulated (state licenses) | Single point of failure risk |
| Public company accountability | Clients can’t sign messages |
BitGo
BitGo is the leading multi-signature custody provider, popular with companies wanting more control over their keys.
Multi-Sig Architecture Options
| Configuration | How It Works | Use Case |
|---|---|---|
| 2-of-3 | Client + BitGo + backup | Standard corporate |
| 3-of-5 | More signers required | High-security needs |
| Custom | Flexible arrangements | Enterprise requirements |
Pros and Cons
| ✅ Pros | ❌ Cons |
|---|---|
| Client holds backup keys | More operational complexity |
| Better proof of reserves | Smaller than Coinbase |
| $250M Lloyd’s insurance | Less liquidity for trading |
| Flexible multi-sig options | Requires technical expertise |
Fidelity Digital Assets
Fidelity Digital Assets brings traditional finance credibility to crypto custody. Popular with companies that prioritize TradFi relationships.
Who Uses It
Companies choosing Fidelity typically: - Have existing Fidelity brokerage/retirement relationships - Need a “safe” brand name for board approval - Come from traditional finance backgrounds
Pros and Cons
| ✅ Pros | ❌ Cons |
|---|---|
| TradFi credibility and compliance | Less crypto-native expertise |
| Familiar to boards/audit committees | Smaller crypto operation |
| Long regulatory track record | Less integrated trading |
| Growing institutional focus | Limited proof of reserves |
Emerging Options
The custody landscape is evolving. Several alternatives are gaining traction:
| Provider | Model | Key Feature |
|---|---|---|
| Anchorage Digital | Full custodial | Federally chartered crypto bank |
| Unchained | Collaborative (2-of-3) | Client controls 2 keys, can prove holdings |
| Self-custody | Full control | Companies like River use this |
Unchained (Collaborative Custody)
This model deserves special attention for proof-of-reserves-focused companies:
How it works: 2-of-3 multi-sig where client holds 2 keys, Unchained holds 1. Client maintains control AND can prove holdings cryptographically. Best of both worlds.
Comparison Table
Summary comparison of major custody providers:
| Provider | Security | Insurance | Proof of Reserves | Control |
|---|---|---|---|---|
| Coinbase Prime | ★★★★★ | ★★★★★ | ★★☆☆☆ | ★★☆☆☆ |
| BitGo | ★★★★☆ | ★★★★☆ | ★★★★☆ | ★★★★☆ |
| Fidelity | ★★★★☆ | ★★★★☆ | ★★☆☆☆ | ★★☆☆☆ |
| Unchained | ★★★★☆ | ★★★☆☆ | ★★★★★ | ★★★★★ |
How to Choose
The right custody solution depends on your priorities:
Prioritize Simplicity and Liquidity → Coinbase Prime
Best for: Companies that want one-stop-shop custody and trading, are comfortable with centralized custody, and prioritize brand recognition.
Prioritize Control and Flexibility → BitGo
Best for: Companies that want key ownership, need custom multi-sig arrangements, and have operational capability to manage keys.
Prioritize TradFi Credibility → Fidelity
Best for: Companies with existing Fidelity relationships, boards that need a “safe” name, and those prioritizing traditional finance compliance.
Prioritize Proof of Reserves → Unchained or Self-Custody
Best for: Companies that want to prove holdings cryptographically, are comfortable with operational complexity, and prioritize transparency.
Frequently Asked Questions
Can we use multiple custodians?
Yes, and many large holders do. Diversifying custody reduces single-point-of-failure risk. However, it adds operational complexity and may complicate proof of reserves.
What insurance do we need?
Most custodians provide crime/theft coverage. You may want additional directors & officers coverage and cyber insurance. Consult with an insurance broker familiar with crypto.
How does custody affect proof of reserves?
Significantly. Self-custody allows you to sign messages proving ownership. Third-party custody means relying on custodian attestations. If proof of reserves matters to you, prioritize custody solutions that enable it.
What questions should we ask custodians?
| # | Question | Why It Matters |
|---|---|---|
| 1 | How are keys secured? | Understand their security model |
| 2 | What’s insurance coverage and limits? | Know your protection |
| 3 | Can you provide proof of reserves? | Critical for transparency |
| 4 | What happens if you’re hacked? | Understand recovery process |
| 5 | What’s your disaster recovery? | Business continuity |
The Bottom Line
Custody is a strategic decision, not just an operational one. Your choice affects security, compliance, and your ability to prove holdings to shareholders.
Coinbase Prime is the safe default, battle-tested and widely used. But companies prioritizing proof of reserves should consider collaborative custody or self-custody options that allow cryptographic verification.
Choose custody that matches your transparency goals, not just your security requirements.
Learn More About These Custody Solutions
Further Reading
- Bitcoin Treasury Companies with Proof of Reserves: Which companies can prove their holdings
- How to Verify Company Bitcoin Holdings On-Chain: DIY verification guide
- Bitcoin Treasury Accounting in 2025: FASB fair value rules explained
See which custody solutions Bitcoin treasury companies use at BitcoinCompanies.co