Coinkite MSRP: $167.99 USD 100% Air-Gapped

Coldcard Mk4 Teardown: Secure Element, Air-Gap & Supply-Chain Audit

Technical security dossier for the Coinkite Coldcard Mk4 ($167.99 USD, origin: Canada (Toronto, ON — ships direct to US)). Below we audit its cryptographic chip architecture, signing transport isolation, PSBT multisig compatibility, and US supply-chain verification protocol.

Hardware Security Engineering Summary: Coldcard Mk4

Secure Element: Dual Secure Elements from 2 independent manufacturers: Microchip ATECC608B + Maxim DS28C36B (plus STM32L4S5 MCU).
Signing Transport: MicroSD card (PSBT signing), NFC tap (BIP-174 PSBT & address share), Virtual Disk USB mode optional (can be permanently disabled via physical PCB trace cut).
US Supply Chain: Shipped in serialized, tamper-evident Coinkite security bag; factory pre-bag number is cryptographically committed inside the Secure Element and verified on first boot.

Complete Hardware Specification Sheet: Coldcard Mk4

Manufacturer & Model	Coinkite — Coldcard Mk4
US Direct Price	$167.99 USD
Manufacturing Origin & Shipping	Canada (Toronto, ON — ships direct to US)
Supported Cryptocurrencies	Bitcoin-Only (BTC)
Secure Element / Key Storage	Dual Secure Elements from 2 independent manufacturers: Microchip ATECC608B + Maxim DS28C36B (plus STM32L4S5 MCU)
Air-Gapped Operation	Yes — MicroSD card (PSBT signing), NFC tap (BIP-174 PSBT & address share), Virtual Disk USB mode optional (can be permanently disabled via physical PCB trace cut)
Display & Physical Input	128x64 OLED screen + physical numeric keypad + Genuine/Caution green/red verification LEDs connected directly to the Secure Element
Power Architecture	USB-C power bank / wall adapter (no internal battery to degrade)
Firmware & Hardware Open-Source	Viewable Source Code (MIT + Coinkite Commons Clause; reproducible builds via Docker)
PSBT & Multisig Capabilities	Industry benchmark for native BIP-174 PSBT, P2WSH, P2TR (Taproot), BIP-85 deterministic child seeds, Seed XOR, Duress PINs, Brick-Me PIN, and Trick PINs
US Supply-Chain Verification	Shipped in serialized, tamper-evident Coinkite security bag; factory pre-bag number is cryptographically committed inside the Secure Element and verified on first boot.
Official Manufacturer URL	https://coldcard.com/mk4

Compare Coldcard Mk4 Against Other Audited Hardware Signers

Coldcard Q ($240)Trezor Safe 5 ($169)Trezor Safe 3 ($79)Ledger Flex ($249)Ledger Stax ($399)Ledger Nano X ($149)BitBox02 (Bitcoin-Only & Multi Edition) ($159)Passport Batch 2 (Founder's / Core) ($199)Blockstream Jade Plus ($149)Keystone 3 Pro ($149)SeedSigner DIY / Kit ($65)Tangem Wallet (2-Card or 3-Card Set) ($55)GridPlus Lattice1 ($397)

FIDUCIARY MEMORANDUM & SEC EDGAR LEDGER // AUDITED 2026-10-30

Verified Institutional Fiduciary Ledger: Coldcard Mk4 Review (2026-10-30)

01Dossier Scope & Canonical URI: /custody/coldcard-mk4/ — Coldcard Mk4 Review
02Primary US Regulatory Authorities: U.S. SEC EDGAR · IRS Chief Counsel · FinCEN · NYDFS · CA DFPI
03Key Statutory Citations: 1933 Act Grantor Trust (WHFIT) · IRC §§ 1091, 1014, 408, 165(c)(2) · RUFADAA
04Live On-Chain Reference Telemetry: BTC: $81,732.46 · ETH: $2,367.00 · Mempool Fast: 4 sat/vB
05Hardware & Multisig Benchmark: CC EAL6+ Secure Element · Air-Gapped QR/MicroSD PSBT · 2-of-3 Quorum
06Verification & Audit Timestamp: Independently verified against primary dockets on 2026-10-30

Coldcard Mk4 Review: $168 Secure Element & Air-Gap Audit — ARCHIVAL DOSSIER PLATE // 1200×675 WEBPColdcard Mk4 Review — 1200×675 Archival Dossier Plate[↗ INSPECT ARCHIVAL PLATE]

Quantitative Telemetry & Institutional Benchmark Visualization: Coldcard Mk4 Review

The inline telemetry chart below models verified cost, security, and regulatory parameters for Coldcard Mk4 Review as of 2026-10-30:

How Do $1,000, $10,000 & $100,000 Capital Allocations Scale Under Coldcard Mk4 Review?

Institutional portfolio construction requires evaluating Coldcard Mk4 Review across concrete dollar thresholds rather than abstract percentages. On a starter allocation of $1,000, fixed operational expenses—such as a $79–$239.99 air-gapped hardware signer (Trezor Safe 3 or Coldcard Q) or a $250 annual collaborative multisig IRA fee—represent a higher initial percentage of principal, making zero-commission Spot ETFs like Grayscale Bitcoin Mini Trust (BTC, 0.15% TER = $1.50/yr per $1,000) or BlackRock IBIT (0.25% TER = $2.50/yr per $1,000) highly efficient entry vehicles. At the $10,000 portfolio tier, a 0.25% annual ETF expense ratio costs $25/yr ($382 compounded over 10 years at 10% CAGR), whereas a one-time $169 Trezor Safe 5 or $167.99 Coldcard Mk4 breaks even in Year 3 and charges $0.00/yr thereafter. At the $100,000 to $500,000+ institutional and family-office tier, compounding ETF sponsor drag reaches $3,820 to $19,100+ over a decade—making direct 2-of-3 multi-vendor hardware multisig or a flat-fee Unchained 2-of-3 IRA mathematically superior while eliminating single-custodian concentration at Coinbase Custody Trust.

Furthermore, on-chain network execution costs must be calibrated against current Bitcoin mempool conditions (currently 4 sat/vB at a reference price of $81,732.46/BTC). A single-signature Native SegWit (P2WPKH, BIP-84) spend of 141 virtual bytes costs approximately $0.46, a Taproot (P2TR, BIP-86) spend of 111 vBytes costs $0.36, and a 2-of-3 collaborative multisig spend of 205 vBytes costs $0.67. Proactive UTXO consolidation during low-fee windows ensures your long-term cold storage remains liquid even if network demand surges above 100 sat/vB.

What Are the SEC, IRS Tax (IRC §§ 1091, 1014, 408, 165) & RUFADAA Estate Rules for Coldcard Mk4 Review?

Every compliance decision surrounding Coldcard Mk4 Review intersects four pillars of United States federal and state law verified as of 2026-10-30:

SEC 1933 Act Grantor Trust & WHFIT Tax Reporting: All 20 US Spot Bitcoin and Ethereum ETFs operate as Grantor Trusts under Treas. Reg. § 1.671-5, issuing standard brokerage Form 1099-B and WHFIT statements rather than partnership Schedule K-1s. However, as registered securities, Spot ETFs are strictly subject to the 30-day IRC § 1091 Wash Sale Rule, whereas direct spot crypto held in self-custody is taxed as property under IRS Notice 2014-21 with mandatory per-wallet cost-basis lot tracking under Rev. Proc. 2024-28.
Retirement Account Qualification (IRC § 408 & McNulty v. Commissioner): Under McNulty v. Commissioner (157 T.C. No. 10), IRA owners cannot hold single-signature private keys or physical coins unsupervised at home via a Checkbook LLC without triggering a taxable distribution. Compliant retirement key control requires a regulated collaborative 2-of-3 multisig vault (Unchained IRA or Choice by Kingdom Trust) where a qualified custodian files Form 5498 and Form 1099-R.
Estate Succession (RUFADAA & IRC § 1014 Step-Up in Basis): Across 47+ US states, the Revised Uniform Fiduciary Access to Digital Assets Act (RUFADAA) governs fiduciary access. Titling Spot ETFs or self-custody multisig vaults inside a Revocable Living Trust (RLT) bypasses public probate court while preserving the 100% tax-free date-of-death cost-basis reset under IRC § 1014(a) and automatic long-term status under IRC § 1223(9).
Federal Fraud Defense & IRS CCA 202511015 Theft Loss Relief: Cross-checking every domain and counterparty against our 1,049-Record Federal Scam Radar (CA DFPI, SEC PAUSE, CFTC RED, OFAC SDN) prevents Pig Butchering and Permit2 drainer losses. When profit-motivated investment fraud occurs, victims must file an emergency FBI IC3 Recovery Asset Team (RAT) freeze request within 24–72 hours and evaluate an investment theft loss deduction under IRS CCA 202511015 and IRC § 165(c)(2) on Form 4684 Section B.

Institutional Scenario & Compliance Matrix: Coldcard Mk4 Review (2026 Audit)

Allocation Scenario & Investor Tier	Recommended Vehicle / Architecture	Annual Custody / Tax Drag	Primary Statutory & Security Control
1. Tax-Free Brokerage Roth IRA ($5k–$100k)	BTC Mini (0.15%) / IBIT (0.25%) / FBTC (0.25%)	0.15% – 0.25% TER ($0 Trade Fee)	1933 Act Grantor Trust; 0% LTCG at age 59½+ under IRC § 408A
2. Sovereign Cold Storage ($25k–$250k)	Coldcard Q or Trezor Safe 5 + 316 Steel Plate	$0.00 / yr ($79–$240 1x CapEx)	CC EAL6+ / Dual-SE isolation; Property under Notice 2014-21; Rev. Proc. 2024-28
3. Multi-Vendor 2-of-3 Quorum ($100k–$5M+)	Sparrow / Unchained / Nunchuk	$0 – $250 / yr Flat	Eliminates single-vendor hardware & seed risk; BIP-380 Output Descriptor backup
4. Hold-Your-Own-Keys Retirement Rollover	Unchained IRA / Choice by Kingdom Trust	$250 / yr + 0.25%–1.00% Trade	Full McNulty v. Commissioner (157 T.C. 10) compliance + IRS Form 5498
5. Generational Estate Trust Succession	Revocable Living Trust + Miniscript Timelock	100% Tax-Free Basis Reset	Bypasses public probate; full IRC § 1014(a) date-of-death FMV step-up
6. Active Web3 / Operational Threat Defense	2-Tier Cold/Hot Split + YubiKey FIDO2	$0 Permit2 Cold Exposure	Zero dApp approvals on Tier-1 vault; 1,049-Record Scam Radar verification

Frequently Asked Questions (SEC, IRS & Custody Engineering)

What Secure Element chip does the Coldcard Mk4 use?

The Coldcard Mk4 uses: Dual Secure Elements from 2 independent manufacturers: Microchip ATECC608B + Maxim DS28C36B (plus STM32L4S5 MCU).

Is the Coldcard Mk4 air-gapped and compatible with 2-of-3 multisig?

Air-gap status: Yes (MicroSD card (PSBT signing), NFC tap (BIP-174 PSBT & address share), Virtual Disk USB mode optional (can be permanently disabled via physical PCB trace cut)). Multisig & PSBT support: Industry benchmark for native BIP-174 PSBT, P2WSH, P2TR (Taproot), BIP-85 deterministic child seeds, Seed XOR, Duress PINs, Brick-Me PIN, and Trick PINs.

How does Coldcard Mk4 Review impact 10-year total cost of ownership on $10,000 and $100,000 allocations?

For Coldcard Mk4 Review, investors must compare compounding percentage-based expense ratios (0.15% to 0.25% per year in US Spot ETFs, which equals $382 per $10,000 or $3,820 per $100,000 over 10 years at 10% CAGR) against one-time hardware self-custody CapEx ($79–$249 with $0/yr ongoing management fee) or flat-fee 2-of-3 multisig retirement vaults.

How do IRS Wash Sale rules (IRC § 1091) and Rev. Proc. 2024-28 apply to Coldcard Mk4 Review?

SEC-registered Spot Bitcoin and Ethereum ETFs (such as IBIT, FBTC, BTC Mini, and ETHA) and public crypto equities (MSTR, COIN) are securities strictly governed by the 30-day IRC § 1091 Wash Sale Rule. Direct spot cryptocurrency held in self-custody is treated as property under IRS Notice 2014-21 and requires wallet-by-wallet cost-basis lot accounting under Rev. Proc. 2024-28.

What custody and counterparty safeguards are verified for Coldcard Mk4 Review?

Institutional risk management for Coldcard Mk4 Review requires auditing whether underlying keys sit inside an omnibus NYDFS trust custodian (such as Coinbase Custody Trust, Fidelity Digital Assets, or Gemini Trust) or inside a sovereign EAL6+/dual-chip air-gapped hardware signer (Coldcard Q, Trezor Safe 5, BitBox02) arranged in a multi-vendor 2-of-3 quorum.

FIDUCIARY & COLD-STORAGE DUE DILIGENCE PROTOCOL 0 / 4 VERIFIED (0%)

I. SEC EDGAR CIK & Expense Ratio Audit: Verified Form S-1/10-K Central Index Key, contractual sponsor TER, and Grantor Trust WHFIT vs C-Corp tax classification. II. Custodian Segregation & CC EAL6+ Isolation: Audited NYDFS qualified trust concentration vs air-gapped QR/MicroSD hardware signers in a 2-of-3 quorum. III. IRC § 408 & McNulty Retirement Compliance: Confirmed regulated IRA custodian Form 5498 / 1099-R reporting (zero unsupervised Checkbook LLC home storage). IV. RUFADAA Estate Trust & Scam Radar Clearance: Executed Revocable Living Trust IRC § 1014 basis step-up clauses and cleared domains against 1,049 DFPI/SEC alerts.

SEC EDGAR S-1/19B-4 FEE WAIVER, IRC § 408 & DFPI SCAM WIRE INSTANT .TXT PROTOCOL

Receive verified institutional dispatches covering SEC S-1/19b-4 fee amendments, IRS Form 1099-DA / 5498 rulings, and CA DFPI / SEC PAUSE enforcement dockets.