Fixed-rate lending has genuine on-chain demand. The obvious response is to issue fixed-rate loans, but there is no matching on-chain demand for fixed-rate lending. The vast majority of on-chain capital chases yield and craves immediate liquidity. As a result, issuing fixed-rate loans merely transfers interest rate risk from borrowers to lenders. And when the lender is a treasury that promises immediate liquidity, this creates an asset-liability mismatch.

In variable-rate lending, interest rates float with utilization and market conditions, and borrowers pay directly for this volatility. This is a real cost—but one that is transparent and terminates upon position closure. Suppose a lender holds a 6-month fixed-rate loan at 3%. If rates rise, the same loan would now yield 5%. Marked-to-market (MTM), the value of the old loan shrinks. With higher-yielding new loans available at equivalent risk, no one will pay the old loan’s amortized value. For a single, isolated loan, MTM losses remain purely on-paper—because the lender can hold to maturity and receive full repayment. Only when that loan is placed inside a system requiring continuous pricing does it become highly dangerous. Morpho’s V2 Treasury is currently the most representative publicly disclosed design embedding fixed-rate loans into a treasury committed to immediate liquidity.

From publicly available information, this design comprises three components:
– Morpho Blue, the existing variable-rate lending protocol, where lenders deposit funds into isolated markets and borrowers pay rates that float with utilization; positions can be opened and closed at any time.
– Morpho Midnight, a fixed-rate, fixed-term lending mechanism powered by zero-coupon bonds (ZCBs), where borrowers and lenders are matched via an intent engine; each loan is structured as a bond with specific collateral, term, and rate—and these ZCBs are permissionless, supporting arbitrary combinations of collateral, term, and parameters.
– Morpho V2 Treasury, a curator-managed treasury that allocates deposits between Blue and Midnight based on yield; depositors mint and redeem shares at the treasury’s share price.

Imagine two competing USDC-denominated treasuries: Treasury A allocates funds to both Blue and Midnight; Treasury B allocates exclusively to Blue. Treasury A allocates 30% to Blue (variable, 3%) and 70% to Midnight (fixed, 3%). A rate shock pushes the variable rate up to 5%, while Midnight positions remain locked at 3%. Treasury A’s blended yield rises to 3.6% (5% × 30% + 3% × 70%). The purely variable-rate Treasury B jumps to 5%. That 140-basis-point gap creates both the condition and incentive for a treasury run.

Depositors in Treasury A need not calculate MTM losses—or even know they exist. The yield differential itself acts as a coordination mechanism. Capital flows from A to B chasing higher yields, exiting A exclusively through its only liquid component—the variable-rate module. This drains the highest-yielding portion first, further depressing Treasury A’s blended yield and accelerating the run. What remains is a pile of illiquid, below-market-rate fixed loans, stuck until maturity.

Now reverse the scenario. When rates fall, Treasury A’s fixed positions outperform the market. Depositors enjoy MTM gains—but cannot lock them in. Depositors in Treasury B, sensing Treasury A’s higher blended yield, rush in to capture a share. New capital enters at the current share price and is proportionally allocated across the existing book. That means new money enjoys the same proportional claim on those above-market-rate positions as the original depositors—diluting those gains outright. It’s a lose-lose. Rates rise: depositors flee, treasury runs. Rates fall: gains get diluted.

The core problem lies in how bonds are priced. Though accounting treatments for ZCB amortization vary, setting that aside, the real issue is that external rate changes alter a bond’s true economic value—yet amortization-based pricing fails to reflect that reality. Price bonds using amortized value, and the asymmetry described above inevitably follows. The obvious fix is to build a secondary market, which—in theory—would allow treasuries to price bonds at fair value. Yet no viable secondary market can form around permissionless ZCBs with arbitrary collateral, term, and parameters—because each bond is effectively unique, lacking any liquid benchmark for pricing.

Even granting, hypothetically, that such a secondary market did emerge, pricing the treasury against it would merely mask one problem with a worse one. Share prices would hinge on external trading data for bespoke, illiquid bonds. Anyone capable of influencing that data could manipulate share prices—and arbitrage inflows and outflows from the treasury. Expressive zero-coupon bonds and treasuries promising immediate liquidity are structurally incompatible. Perhaps some internal resolution exists within this architecture—but I’ve yet to see it described, and I’m deeply curious whether Morpho has already devised a solution.

That said, I personally believe issuing fixed loans directly is not the answer—at least not in the near-term horizon of overcollateralized lending. If borrowers want fixed rates and lenders demand immediate liquidity, then interest rate risk must be transferred to parties willing to take on that targeted risk exposure. And if the underlying variable-rate benchmark curve becomes increasingly efficient and robust, buyers of rate risk can offer better fixed rates. As explored in this piece, we’re far from having reached the final form of variable-rate market design.

[ChainCatcher]