Security alert · Coldcard hardware wallet

Move your Bitcoin off any Coldcard seed created since March 2021 — today.

A firmware bug made affected Coldcards generate seed phrases with a predictable software RNG instead of the chip's hardware RNG. Attackers have already reconstructed the private keys offline and drained roughly 1,719 BTC across three confirmed waves, without ever touching a device — and a suspected fourth wave is still being traced. Updating the firmware does not repair a seed that already exists. If your seed was generated on a Coldcard on or after March 2021, treat it as compromised: move the coins now to a new seed on patched firmware, to a different hardware wallet, or — if you need somewhere immediately — to an exchange you already use, and sort out longer-term custody after the coins are safe.

Watch for follow-on scams. Events like this draw fake “migration” and “wallet checker” sites. Coinkite will never ask for your seed words, and no legitimate tool needs them. Type coldcard.com in by hand rather than following links from social media or email.

Am I affected? Version list and migration steps

The flaw cut seed randomness from the intended 128 bits to roughly 40 bits on Mk2/Mk3 and 72 bits on Mk4/Mk5/Q. Your seed is at risk if you generated it on the device while running:

  • Mk2 / Mk3 — 4.0.1 through 4.1.9
  • Mk4 / Mk5 — anything before 5.6.0 (standard) or 6.6.0X (Edge)
  • Q — anything before 1.5.0Q (standard) or 6.6.0QX (Edge)

Two exceptions. Coinkite states seeds are not at risk from this bug if you supplied at least 50 fair, independent rolls through Add Dice Rolls and those rolls were never recorded or exposed. Seeds generated before firmware 4.0.1 (March 2021) are also outside the affected range. If you are not certain which applies to you, assume you are affected and move the coins.

If a sweep is already under way. Galaxy Research reports that some fourth-wave transactions have replace-by-fee enabled. If you find an unconfirmed transaction spending from your address sitting in the mempool, you may have a short window to broadcast your own higher-fee transaction and move the coins before the attacker's confirms. Galaxy also counts at least 15 separate attackers working through the remaining vulnerable addresses, so assume the sweeping is still going on.

Migration. Update the firmware, generate a brand-new seed, verify the backup and a receive address, send a test transaction, then move the remaining funds. Keep the old backup until the migration is confirmed.

Independent tracing by Galaxy Research attributes roughly 1,719 BTC (about $111M) drained across three confirmed waves, as of Aug 7, 2026 — up from 1,596 BTC on Aug 4, when Galaxy last put the address count at about 7,300. Counting a suspected but still unconfirmed fourth wave, Galaxy puts the possible total near 2,055 BTC (~$130M) across more than 7,700 addresses. Figures were still rising at the time of writing. Bitcoin Lending Intel is not affiliated with Coinkite and this is not financial advice. Verify firmware versions and guidance against Coinkite's own advisory before acting.
Guide Miners & treasury Updated 25 Jun 2026

Bitcoin loans for miners

Mining throws off Bitcoin but eats cash — power, payroll, hardware. Selling your mined BTC to cover it means giving up the upside and usually a taxable bill. Borrowing against your treasury keeps the coins working. Here's how miner lending actually works, the risk that's unique to miners, and how to pick a lender — explained independently.

The short version Miners have two main ways to raise debt: borrow against their mined BTC treasury (cheaper — typically single-to-low-double-digit rates at 40–70% LTV, with margin calls) or use ASIC / hashrate financing secured by the hardware itself (pricier, ~13–28% all-in, harder to margin-call, and it burned lenders in past downturns). If you hold BTC, treasury-collateral loans are usually the cheaper capital. The catch unique to miners: a price crash hits your collateral and your revenue at the same time, so borrow at a conservative LTV and keep a buffer.

Why miners borrow instead of selling

A miner's costs are relentless and denominated in fiat — electricity, hosting, payroll, debt service, new rigs — while the revenue arrives as Bitcoin. The instinct is to sell mined BTC to cover the bills. But selling has two costs: you give up the upside if Bitcoin appreciates, and a sale is generally a taxable disposal that realizes capital gains. Borrowing against the treasury sidesteps both — you fund operations with cash while keeping the coins, and a loan is generally not a taxable event the way a sale is. We cover that mechanism in depth in borrowing against Bitcoin without selling. The same logic that makes loans attractive to long-term holders applies doubly to miners, who are effectively forced sellers if they don't have another source of liquidity.

Two ways to finance a mining operation

When miners raise debt, it's almost always one of two structures:

 BTC-treasury collateral loanASIC / hashrate financing
Secured byYour mined BitcoinThe mining hardware or its production
Typical cost~4–12% (varies by lender/market)~13–28% all-in, often ~18-month terms
Typical LTV40–70%Often sub-50% (hard to margin-call)
Best forMiners holding a BTC treasuryMiners without large reserves who need rig capital
Main riskBTC price drop → margin call / liquidationHardware value falls, loan goes underwater; tougher to unwind

If you already hold Bitcoin, the treasury-collateral route is almost always the cheaper capital, and it's the market this site tracks. ASIC and hashrate financing exists to solve a different problem — getting capital to miners who don't yet have reserves — and it's priced accordingly. A few lenders now blend the two, accepting hashrate, infrastructure and Bitcoin in one collateral package.

The risk that's unique to miners: double exposure

Every Bitcoin-backed borrower faces liquidation risk if the price falls. Miners face it twice over. A sharp drawdown lowers the value of your collateral — pushing your loan-to-value toward the liquidation threshold — at the very same moment it cuts your mining revenue, since each block reward is suddenly worth less in fiat. The two squeezes hit together: exactly when you'd need to add collateral or pay down the loan, your cash flow is thinnest. That correlation is why miner lending should be more conservative than a passive holder's, not less.

Protect yourself Borrow well below the maximum LTV (many miners target 30–40% rather than 60%+), keep a cash or BTC buffer you can post in a crash, and model the downside first. Use the liquidation calculator to see the exact Bitcoin price that would trigger liquidation for your loan size and LTV — then assume it could happen during a revenue slump and ask whether you'd survive it.

Terms a miner should weigh

Which lenders suit miners

Several lenders we track work well for borrowing against a mined treasury. There's no single "best" — it depends on whether you're optimizing for regulation, custody control, or cost:

Regulation & insured custody

  • APX Lending runs a program aimed specifically at North American miners — segregated, insured, non-rehypothecated custody, regulated in Canada, with relatively fast funding
  • Good fit if you run a registered operation and want a clean counterparty

Keep-your-keys custody

  • Unchained uses collaborative multisig — you hold a key, so your treasury can't be rehypothecated or lost in a lender failure
  • Good fit if custody control is your top priority for a working balance sheet

Other CeFi lenders in the comparison table — including Arch and Ledn — also lend against BTC treasury; weigh their rate, LTV, liquidation level and custody the same way. For larger facilities, see best Bitcoin-backed loans for $100,000+, since many lenders price down by loan size.

A note on ASIC and hashrate financing

If you don't hold enough Bitcoin to borrow against, specialized providers offer financing secured by the rigs themselves or by future production. This unlocks capital a treasury loan can't — but be clear-eyed about the trade-offs: it's materially more expensive (often roughly 13–28% all-in), terms are usually shorter (around 18 months), and because ASICs are hard to margin-call, the 2022 downturn pushed many of these loans underwater when hardware values collapsed. We don't rank ASIC/hashrate lenders — the market is specialized and opaque — but miners should know the option exists, and should treat the higher rate as the price of capital without a BTC balance sheet. If you do have treasury, compare it against a much cheaper collateral loan first.

Step by step: borrowing against your mining treasury

  1. Size the need conservatively. Borrow what operations require, not the maximum your BTC allows — your double exposure means a smaller loan is a much bigger safety margin.
  2. Model a revenue-slump crash. Use the liquidation calculator to find your liquidation price, then stress-test it against a scenario where mining income is also down.
  3. Compare lenders on rate, LTV, liquidation level, custody and funding speed in the comparison table; read the risk rating for any lender you're considering.
  4. Confirm terms at the source. Rates and miner-specific programs change — verify on the lender's own site before committing (every row links to it).
  5. Borrow, then monitor LTV against both prices and production — and keep a buffer you can post quickly.

FAQ

Why borrow against mined BTC instead of selling it?

Selling gives up future upside and is generally a taxable disposal. Borrowing funds operations while keeping the coins, and a loan is generally not a taxable event the way a sale is. This is general information, not tax advice — confirm with a professional.

Treasury loan or ASIC financing — which is cheaper?

If you hold Bitcoin, a treasury-collateral loan is almost always cheaper (single-to-low-double-digit rates) than ASIC/hashrate financing (~13–28% all-in). ASIC financing exists for miners without reserves and is priced for that.

Why is liquidation riskier for miners?

A price crash lowers your collateral value and your mining revenue simultaneously, squeezing you from both sides right when adding collateral is hardest. Borrow at a low LTV and keep a buffer.

Which lenders work with miners?

Among lenders we track, APX Lending runs a regulated miner-focused program, and Unchained offers keep-your-keys collaborative custody; other CeFi lenders also lend against treasury. Compare terms in the table before deciding.

How much can I borrow against my treasury?

Up to the lender's maximum LTV (commonly 40–70%), but miners are usually better served borrowing well below it to absorb a downturn.

Compare lenders that work with miners

Rate, LTV, liquidation level, custody and fees for every lender we track — independently verified, with a source link on every row.

Open the comparison →

Get weekly Bitcoin loan rate changes

One short email a week: which lenders moved rates, new terms, and shifts in liquidation risk. Free, no spam, unsubscribe anytime.