Coinbase's 'Fixed-Rate' Bitcoin Loan Is a 2-to-37-Day Term Note on a $4.8M Pool: Morpho Midnight Has $3.1M Borrowed vs $1.46B in Coinbase's Variable cbBTC/USDC Market at 4.92%; Maturities Are the Last Friday of This Month (25 Sept) or Next, and Unpaid Debt Is Liquidated at Expiry, Not Rolled
The parent card is accurate but thin, and it reads like a rate-lock story. The measured picture is narrower. Coinbase's 'fixed-rate' USDC loan against bitcoin, announced 22 Sept 2026, is a fixed-term note with a maximum tenor of about five weeks, settled on a protocol whose entire balance sheet is roughly 0.3% of the variable-rate book it sits beside.
What was launched. Per The Block (22 Sept 2026), Coinbase now lets users borrow USDC against BTC with the rate and repayment date set at origination. Only two maturities are offered: the end of the current month or the end of the next month, where 'end of month' means the last Friday of the month. For a loan opened on 23 Sept that is either Friday 25 Sept (two days, and the same day as the $16B Deribit options expiry) or Friday 30 Oct (37 days). Coinbase declined to tell The Block what rates it is quoting. The loans run on Morpho Midnight, the fixed-rate, fixed-term protocol Morpho launched on Base on 21 July 2026 (The Block, July 2026), not on Morpho Blue, which powers Coinbase's existing floating-rate loans.
How the rate is set. Morpho's Midnight documentation is explicit: 'the rate emerges from the price at which units are traded, not from an interest rate model.' Lenders and borrowers trade standardised credit and debt units in an onchain order book; the app converts the bid or ask price into an implied fixed rate. This matters for what happens at expiry. The docs state that 'after maturity, unpaid debt can be partially or fully liquidated.' There is no automatic roll. A borrower who wants to stay borrowed on 31 Oct must repay or re-enter the order book at whatever the November price is. Fixed-rate here removes intra-month rate drift and replaces it with rollover risk every four to five weeks.
How big it is. DefiLlama's protocol feed (fetched 23 Sept 2026, 12:30 UTC) shows Morpho Midnight at $4.83M total TVL, of which $4.68M on Base, and $3.06M borrowed on Base ($3.19M across chains). The Block put Midnight deposits at 'about $30 million', so take the range as $5-30M depending on what is counted. Either way it is tiny against the market it is meant to complement. Morpho's own API (blue-api.morpho.org, queried 23 Sept 2026) shows the listed Coinbase cbBTC/USDC market on Base (LLTV 86%, marketId 0x9103c3b4...) with $1,459.9M borrowed against $3,254.4M of cbBTC collateral, $1,620.7M supplied, utilisation 90.1%, borrow APY 4.92%, supply APY 4.42%. That matches The Block's '$1.4 billion outstanding against about $3 billion in collateral'. Aggregate LTV on the Coinbase book is therefore 44.9%, well below the 86% liquidation line. The Block also gives Morpho Blue overall at $5.2B outstanding on $16B deposits; DefiLlama shows Morpho Blue TVL at $11.0B. Midnight's $3.1M borrowed is 0.2% of the Coinbase variable market alone.
What a borrower is actually choosing between. The Coinbase variable market has been at or near the 90% target utilisation of its interest-rate model for months, which is why the floating borrow rate sits at 4.92%, only about 100 bp over the 3.75-4.00% federal funds range the FOMC set on 16 Sept 2026. The obvious competitor for a genuinely fixed rate is the CeFi lenders the parent card's source mentions. Ledn's published schedule (fetched 23 Sept 2026) is 11.49% APR under $250k stepping down to 9.25% at $2M+, fixed for a standard 12-month term, opened at a typical 50% LTV with automatic liquidation at 80%. So the real menu today is: Coinbase floating at 4.92% with an 86% liquidation threshold and interest that reprices every Base block; Coinbase fixed for 2-37 days at an undisclosed order-book rate on a $5-30M pool; or Ledn at roughly double Coinbase's floating rate but fixed for a year. A 12-month fixed-rate loan is not on offer at Coinbase.
Loan mechanics unchanged from the 2025 product. The Block's 1 Oct 2025 report on Coinbase crossing $1B of onchain loans (eight months after the January 2025 launch) documents the parameters that still apply: BTC is converted 1:1 to cbBTC and posted to a Morpho contract; the loan cap is $5M USDC per borrower (raised from $1M); minimum collateralisation is 133%; liquidation is triggered at 86% LTV. Coinbase is the front end and custodian of the wrapped BTC; the lenders are Morpho vault depositors, not Coinbase. The parent card's phrase 'expands regulated, exchange-integrated borrowing options' is fair on the front end but the credit itself is non-custodial DeFi on Base, which the card does not say.
What the headline source gets wrong. CoinDesk (23 Sept 2026) sizes 'the bitcoin-backed credit market' at roughly $16B citing the Apyx/BitcoinTreasuries.net 'Bitcoin Digital Credit Report' and floats $130B by 2030 'as preferred equity structures scale'. BitcoinTreasuries.net uses 'digital credit' to mean Strategy-style preferred and convertible instruments (STRK, STRC, etc.), which are corporate securities issued by treasury companies, not loans collateralised by a borrower's coins. Putting Coinbase's $1.46B consumer loan book and Ledn's retail loans in the same $16B bucket as STRC preferreds is a category error; the two grow for different reasons.
Base rate and read-through. Coinbase's variable product went from launch to $1B in eight months and to $1.46B in twenty months, with Brian Armstrong's stated target of $100B in originations still two orders of magnitude away. Midnight's TVL went from $0.9M on 22 July to $4.8M on 23 Sept, i.e. about $2M a month, in a period when Coinbase had not yet turned it on for retail. The next few weeks will show whether a mainstream front end changes that slope. The signal to watch is not the announcement but the 30 Oct maturity: how much of whatever gets borrowed this week is refinanced on Midnight versus paid down or shifted back to floating. Until the Midnight book is measured in hundreds of millions and maturities extend past one quarter, this is an interest-rate feature on top of the existing 86%-LLTV cbBTC market, not new bitcoin-backed leverage.
Sources (6)
AI Research
Key Takeaway
Coinbase's new 'fixed-rate' bitcoin loan is a 2-to-37-day fixed-term note on Morpho Midnight, a protocol with $4.8M TVL and $3.1M borrowed, beside Coinbase's $1.46B variable cbBTC/USDC market at 4.92% and 90% utilisation; unpaid debt is liquidated at maturity, so it trades rate risk for rollover risk rather than adding new BTC-backed leverage.
The parent card is accurate but thin, and it reads like a rate-lock story. The measured picture is narrower. Coinbase's 'fixed-rate' USDC loan against bitcoin, announced 22 Sept 2026, is a fixed-term note with a maximum tenor of about five weeks, settled on a protocol whose entire balance sheet is roughly 0.3% of the variable-rate book it sits beside.
What was launched. Per The Block (22 Sept 2026), Coinbase now lets users borrow USDC against BTC with the rate and repayment date set at origination. Only two maturities are offered: the end of the current month or the end of the next month, where 'end of month' means the last Friday of the month. For a loan opened on 23 Sept that is either Friday 25 Sept (two days, and the same day as the $16B Deribit options expiry) or Friday 30 Oct (37 days). Coinbase declined to tell The Block what rates it is quoting. The loans run on Morpho Midnight, the fixed-rate, fixed-term protocol Morpho launched on Base on 21 July 2026 (The Block, July 2026), not on Morpho Blue, which powers Coinbase's existing floating-rate loans.
How the rate is set. Morpho's Midnight documentation is explicit: 'the rate emerges from the price at which units are traded, not from an interest rate model.' Lenders and borrowers trade standardised credit and debt units in an onchain order book; the app converts the bid or ask price into an implied fixed rate. This matters for what happens at expiry. The docs state that 'after maturity, unpaid debt can be partially or fully liquidated.' There is no automatic roll. A borrower who wants to stay borrowed on 31 Oct must repay or re-enter the order book at whatever the November price is. Fixed-rate here removes intra-month rate drift and replaces it with rollover risk every four to five weeks.
How big it is. DefiLlama's protocol feed (fetched 23 Sept 2026, 12:30 UTC) shows Morpho Midnight at $4.83M total TVL, of which $4.68M on Base, and $3.06M borrowed on Base ($3.19M across chains). The Block put Midnight deposits at 'about $30 million', so take the range as $5-30M depending on what is counted. Either way it is tiny against the market it is meant to complement. Morpho's own API (blue-api.morpho.org, queried 23 Sept 2026) shows the listed Coinbase cbBTC/USDC market on Base (LLTV 86%, marketId 0x9103c3b4...) with $1,459.9M borrowed against $3,254.4M of cbBTC collateral, $1,620.7M supplied, utilisation 90.1%, borrow APY 4.92%, supply APY 4.42%. That matches The Block's '$1.4 billion outstanding against about $3 billion in collateral'. Aggregate LTV on the Coinbase book is therefore 44.9%, well below the 86% liquidation line. The Block also gives Morpho Blue overall at $5.2B outstanding on $16B deposits; DefiLlama shows Morpho Blue TVL at $11.0B. Midnight's $3.1M borrowed is 0.2% of the Coinbase variable market alone.
What a borrower is actually choosing between. The Coinbase variable market has been at or near the 90% target utilisation of its interest-rate model for months, which is why the floating borrow rate sits at 4.92%, only about 100 bp over the 3.75-4.00% federal funds range the FOMC set on 16 Sept 2026. The obvious competitor for a genuinely fixed rate is the CeFi lenders the parent card's source mentions. Ledn's published schedule (fetched 23 Sept 2026) is 11.49% APR under $250k stepping down to 9.25% at $2M+, fixed for a standard 12-month term, opened at a typical 50% LTV with automatic liquidation at 80%. So the real menu today is: Coinbase floating at 4.92% with an 86% liquidation threshold and interest that reprices every Base block; Coinbase fixed for 2-37 days at an undisclosed order-book rate on a $5-30M pool; or Ledn at roughly double Coinbase's floating rate but fixed for a year. A 12-month fixed-rate loan is not on offer at Coinbase.
Loan mechanics unchanged from the 2025 product. The Block's 1 Oct 2025 report on Coinbase crossing $1B of onchain loans (eight months after the January 2025 launch) documents the parameters that still apply: BTC is converted 1:1 to cbBTC and posted to a Morpho contract; the loan cap is $5M USDC per borrower (raised from $1M); minimum collateralisation is 133%; liquidation is triggered at 86% LTV. Coinbase is the front end and custodian of the wrapped BTC; the lenders are Morpho vault depositors, not Coinbase. The parent card's phrase 'expands regulated, exchange-integrated borrowing options' is fair on the front end but the credit itself is non-custodial DeFi on Base, which the card does not say.
What the headline source gets wrong. CoinDesk (23 Sept 2026) sizes 'the bitcoin-backed credit market' at roughly $16B citing the Apyx/BitcoinTreasuries.net 'Bitcoin Digital Credit Report' and floats $130B by 2030 'as preferred equity structures scale'. BitcoinTreasuries.net uses 'digital credit' to mean Strategy-style preferred and convertible instruments (STRK, STRC, etc.), which are corporate securities issued by treasury companies, not loans collateralised by a borrower's coins. Putting Coinbase's $1.46B consumer loan book and Ledn's retail loans in the same $16B bucket as STRC preferreds is a category error; the two grow for different reasons.
Base rate and read-through. Coinbase's variable product went from launch to $1B in eight months and to $1.46B in twenty months, with Brian Armstrong's stated target of $100B in originations still two orders of magnitude away. Midnight's TVL went from $0.9M on 22 July to $4.8M on 23 Sept, i.e. about $2M a month, in a period when Coinbase had not yet turned it on for retail. The next few weeks will show whether a mainstream front end changes that slope. The signal to watch is not the announcement but the 30 Oct maturity: how much of whatever gets borrowed this week is refinanced on Midnight versus paid down or shifted back to floating. Until the Midnight book is measured in hundreds of millions and maturities extend past one quarter, this is an interest-rate feature on top of the existing 86%-LLTV cbBTC market, not new bitcoin-backed leverage.