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What is the cheapest USDC borrow rate right now?

It has no single answer: two venues on the same asset and chain routinely differ by a point. What sets the rate you pay, and the trap that costs more.

Strategy4 min readDeFiLoopsUpdated

In short: there is no single cheapest rate. The same USDC loan on the same chain can cost more than a point more at one venue than at another, and the number that decides what you pay is often not the one you are comparing. The same is true if you are lending dollars to earn interest: supply rates differ too, and on Morpho the collateral you deposit earns nothing at all.

This was typed into the product word for word. The answer is annoying: there is no single cheapest rate, and the number that decides what you actually pay is usually not the one you are comparing.

Start with the size of the spread

Two venues on the same asset, on the same chain, at the same moment routinely differ by more than a percentage point. On $100,000 borrowed that is over $1,000 a year, between venues most people treat as interchangeable.

Where a USDC borrow can come from
Aave v3
Reserves enumerated from the pool itself, so every asset Aave lists, not only the ones we have a name for. One pool per chain, so there is no market to name.
Aave v4
Read from its hub.
Morpho
Curated markets, each named <collateral>-<loan>.
Revert vaults
Borrowing against a liquidity position.

With three networks each, “the cheapest USDC borrow rate” is a question about a dozen or so numbers that move independently.

The advertised rate is a snapshot of a moving thing

Four numbers matter. Most comparisons only show you one.

  1. Borrow APY

    What you are quoted. The one everybody compares.

  2. Utilisation: how much is already borrowed

    This decides where the rate goes next. Lending markets price by utilisation: as more of a pool is borrowed, the rate climbs, often sharply past a kink. A cheap rate at 40% utilisation is safer than a cheap rate at 90%, which is one large borrower away from not being cheap.

  3. The loan-to-value at which it liquidates

    A market decides the price at which you are liquidated. That is a term of the loan, and it can differ between two venues quoting the same rate.

  4. Supply APY

    What the other side earns. Relevant when you are choosing where to put money instead of where to take it from.

The trap that costs more than the spread

This is a mistake people really make, and the numbers look fine while they make it.

Compare that with Aave v3, where a supplied asset both backs your borrow and earns. The two venues use the same word for different things, and the gap is larger than any rate spread you were optimising.

Why “cheapest” is the wrong optimisation anyway

A borrow is a position with terms that last as long as you hold it.

Before

Pick the lowest borrow APY. Move if something cheaper appears.

This ignores utilisation, ignores the liquidation threshold, and ignores what moving costs.

After

Pick a rate you can live with, at a utilisation that will not spike, at a liquidation level that leaves real headroom.

Then leave it alone unless the spread is worth the move.

On headroom specifically: aim well below the ceiling. Collateral bought by an earlier step arrives worth slightly less than was spent, so a plan targeting the maximum loan-to-value starts out tighter than intended. Half is a reasonable default.

Moving the loan, when it is worth it

If the spread does justify a move, automating it saves you a hard step.

By hand, refinancing a loan is a chicken-and-egg problem: to repay the old loan you need your collateral back, and to get your collateral back you have to repay the loan. Your only way through is to find the entire loan amount somewhere else first.

Moving the loan in one instruction
  1. 01move-loanbase
    loan.shiftflash-funded, repaid in the same transaction2 calls
1 steps

The money that frees the collateral is borrowed and repaid inside the same transaction. Either the whole thing happens or none of it does, and your account never holds the borrowed amount.

How to actually get the answer

One call covers every venue.

What comes back is every market’s supply APY, borrow APY, utilisation and liquidation loan-to-value, across Aave v3, Aave v4, Morpho and Revert vaults on all three networks. Omit the filters entirely and you get all of it.

It costs nothing. Of fifty-two tools, five spend money and this is not one of them.

The answer to the original question

There isn’t one number. Anybody who gives you one is quoting a single venue.

What you get instead is a spread worth more than a point between venues most people treat as the same, a utilisation figure that tells you whether today’s rate is likely to hold next week, and one venue where the collateral you supply earns nothing.

Ask for all of it at once, then borrow. Asking is free; only the borrowing costs.