The stablecoin market has scaled past $310 billion, but the overwhelming majority of that capital sits idle, earning no native yield while inflation quietly compounds against it. The alternatives that exist today either fail to outpace inflation, or rely on derivative funding strategies that structurally compress as more capital arrives. Demand for a yield-bearing dollar is settled. The open question is where the yield comes from.

Apyx answers that question by routing a different category of yield onchain entirely: the dividend cash flows of digital credit, the variable-rate perpetual preferred equity issued by Digital Asset Treasury companies (DATs) such as Strategy and Strive. These are publicly listed preferred shares that pay monthly cash dividends, sit senior to common equity, carry no maturity, and adjust their coupons periodically to trade near par. Strategy's STRC currently pays in the 11.5% range; Strive's SATA pays close to 12.75%. Both are funded primarily to support Bitcoin treasury strategies, and both generate transparent, recurring, dollar-denominated cash flows that — until recently — were locked inside brokerage accounts and unreachable from DeFi.

apxUSD, the synthetic dollar issued by Apyx, is the bridge. It aggregates dividend income from a diversified basket of these preferreds and converts that off-chain stream into onchain savings yield, delivered through a standard ERC-4626 vault (apyUSD). The yield is not manufactured by leverage or basis trades. It is the financing cost of public companies' Bitcoin balance sheets, paid in cash, and now wrapped into a token.

Fira turns that token into productive, fixed-rate collateral.

Why PT-apxUSD Belongs in a Fixed-Rate Market

Pendle splits apxUSD into its principal and yield components. Holders of PT-apxUSD have already locked in a fixed return to maturity — the discount is set at entry, the redemption value is one apxUSD per PT at expiry, and the position has a defined duration. That structure is what makes it natural collateral for a fixed-rate credit market. The asset already has a known terminal value; pricing it for a loan that resolves before maturity is a tractable problem.

What it requires is a venue that prices credit the same way the collateral itself is priced: with a fixed rate, set at entry, that does not move with utilization. Floating-rate lending markets cannot offer that. They quote a rate that drifts with pool dynamics, which means a borrower against PT collateral is mismatching a fixed-duration asset against a floating-cost liability. The hedge is incomplete by construction.

Fira removes that mismatch. Rates on Fira are discovered by supply and demand at each maturity and locked when participants commit. A borrower against PT-apxUSD knows their exact repayment from day one. There is no rate accrual, no utilization repricing, no surprise at the end of the loan. For participants running leveraged dividend-yield strategies — borrowing USDC against PT-apxUSD to recycle into more apxUSD exposure — the cost leg of the trade is fixed at the same time the income leg is fixed. The trade is genuinely hedged, not approximately hedged.

What the Collateral Actually Is

apxUSD is over-collateralized, and the collateral is unusually transparent for a yield-bearing stablecoin. The basket is currently dominated by STRC, with SATA and short-duration cash equivalents alongside it, and is rebalanced against issuer concentration, liquidity, and coverage thresholds.

Both STRC and SATA are listed on Nasdaq. Their dividend rates, capital structures, redemption rights, and trading histories are publicly disclosed in offering documents and trade through regulated venues. The assets backing apxUSD are held in custody under third-party prime brokerage accounts in the name of Preference Foundation, segregated from the protocol's operating entity. Apyx publishes monthly third-party attestations prepared by Wolf & Company, P.C., a PCAOB-registered audit firm — examination-level engagements, not the lighter agreed-upon procedures format common elsewhere in the category. A continuously updated dashboard at accountable.apyx.fi provides near real-time visibility into supply, reserves, and coverage between attestations.

This combination — listed underliers, regulated custody, examination attestations, continuous onchain reporting — is what makes apxUSD legible enough to be priced as fixed-rate collateral. A market cannot quote a fixed rate against an opaque asset; the rate would have to absorb the opacity. apxUSD's transparency is what allows the rate quoted on Fira to reflect the asset rather than the uncertainty around it.

PT-apxUSD lists on Fira at an 88% LTV against USDC, with a maturity of June 17, 2026 (which matches the Pendle market’s maturity). The parameter reflects the actual risk profile of the underlying (assessed by our curator, Markov Labs) — preferred equity carries duration sensitivity and BTC-correlated downside that a fiat-backed stablecoin does not — and it is set at the level Fira's risk framework can support without compromising the rest of the protocol.

A Live Example of Onchain Composability

The path from Apyx to Pendle to Morpho to Fira is the most useful way to read this listing. apxUSD launches as a synthetic dollar. Pendle splits it into PT and YT, creating a fixed-yield instrument with a defined maturity. Morpho accepts that instrument as collateral, bringing it into a working lending market. Fira now accepts it at a fixed borrow rate, completing the credit loop with a maturity that aligns to the PT itself.

None of those integrations required bilateral agreements between the underlying asset and each downstream protocol. Each layer is open, permissionless, and asset-agnostic — the asset shows up, meets the standards, and gets composed. For an asset that did not exist a few months ago, apxUSD has accumulated more than $50M in combined Pendle TVL and an active, high-utilization Morpho market. The Fira listing is the next link, and the one that turns PT-apxUSD into something more than a yield instrument: a piece of fixed-rate credit infrastructure.

Two-Sided Markets, On the Roadmap

Today, Fira accepts PT-apxUSD as collateral on its fixed-rate borrow side. Holders who acquired PT-apxUSD through Pendle can borrow USDC at a rate fixed at entry. As the market matures, Fira's roadmap includes apxUSD itself as a lending asset — letting participants supply apxUSD directly and earn a fixed return over a defined maturity.

When both sides are live, apxUSD becomes a full-spectrum credit asset on Fira: borrow against it, lend it, or arbitrage the rate spread between PT-apxUSD and adjacent PT collaterals (PT-USDG, PT-USDe, PT-sUSDe) when implied rates diverge across maturities. apxUSD sits at the higher-yield end of that spectrum, which makes it a natural input for participants running spread strategies between RWA-backed and crypto-native fixed-rate markets.

About apxUSD

apxUSD is the synthetic dollar issued by Apyx, the first dividend-backed stablecoin protocol. Backing comes from a diversified basket of variable-rate perpetual preferred shares issued by Digital Asset Treasury companies, including Strategy's STRC and Strive's SATA, supplemented by cash and short-duration treasuries. Yield generated by the underlying preferreds accrues to apyUSD, the protocol's savings token. apxUSD is live on Ethereum and Base. Apyx is supported by the team behind DeFi Development Corp. (Nasdaq: DFDV).

About Fira

Fira is an autonomous onchain protocol for fixed-rate lending and borrowing. It introduces maturity-based credit markets where rates are discovered by supply and demand, not set by utilization curves. Fira is built by Steady Labs and owned by the Usual DAO. Learn more at fira.money.