Glossary

Every term you'll meet in these docs, defined simply. Linked to the page where each is used in context.

AMM (Automated Market Maker)

A smart contract that lets people trade against a pool of assets at an algorithmic price, instead of matching buyers and sellers directly. Spield's market is a time-decay AMM.

Backing

The live value of the protocol's yield position — the real assets standing behind PT and YT. Spield keeps backing ≥ everything it owes. See Solvency.

Base units

The integer representation of a token amount on-chain. Spield's tokens use 7 decimals, so 10_000_000 base units = 1.0. See Tokens & units.

Blend

Stellar's primary lending market, where Spield sources its yield by supplying USDC. See The yield source.

Bridge

Infrastructure for moving assets between blockchains. Spield offers an optional cross-chain bridge to bring USDC to Stellar; the core protocol itself uses no bridge.

Coupon

The fixed extra amount a Fixed-Rate Vault deposit earns on top of principal — the "interest" portion of your guaranteed payout.

Discount

How far below par (1.0) a PT trades today. The discount is the source of PT's fixed return.

Fixed APY

The annualized return you lock in by buying PT (or depositing in the vault) and holding to maturity. It doesn't change after you commit.

Fixed-Rate Vault

Spield's flagship product: deposit USDC, receive a receipt for a guaranteed payout at maturity. See Fixed-Rate Vault.

Implied APY

The market's current expectation of future yield, read off the PT price. Buying YT is a bet that realized yield will beat the implied APY.

Impermanent loss (IL)

The opportunity cost an LP can face when pool asset prices move. Spield's time-decay design makes IL near zero for LPs who hold to maturity. See Liquidity.

LP / LP shares

A liquidity provider supplies assets to the market; LP shares represent their proportional claim on the pool and its accrued fees.

Maturity

The fixed date when PT becomes redeemable 1:1 for USDC and YT stops earning. Every Spield market has one.

Par

The face value of a PT — exactly 1 USDC. PT prices drift up toward par as maturity nears.

Position

A single deposit, tracked with its own starting point for measuring yield. Precise per-position accounting is why transferring/trading PT and YT is safe.

PT (Principal Token)

The fixed-rate bond leg. Redeems 1:1 for USDC at maturity; bought at a discount today. Symbol SPLDPT. See PT and YT explained.

Realized APY / yield

The yield that actually accrued (as opposed to the implied expectation). Reconstructable from the yield-source rate over time.

Redeem

To exchange a token for what it's owed: PT → 1 USDC at maturity, or a vault receipt → its full payout.

SAC (Stellar Asset Contract)

The smart-contract wrapper that lets a Stellar asset be used by Soroban contracts. PT, YT, and USDC are all SACs. See Tokens & units.

Slippage

The difference between a quoted price and the executed price on a trade. You set a tolerance so trades only execute within an acceptable range.

Solvency

The property that backing ≥ everything owed. Spield is solvent by construction and lets you verify it live.

Soroban

Stellar's smart-contract platform, on which Spield's contracts run.

Stellar

The fast, low-fee blockchain Spield is built on. See Why Stellar?.

Stripping (yield stripping)

Splitting a yield-bearing position into a fixed leg (PT) and a variable leg (YT). The core model behind Spield.

Trustline

A Stellar account's declaration that it's willing to hold a particular asset. The app sets up PT/YT trustlines for you automatically.

USDC

Circle's USD-backed stablecoin, native on Stellar. The asset you deposit and PT redeems into.

XLM

Stellar's native asset, used to pay small network fees and reserves.

YT (Yield Token)

The variable yield leg — a claim on all yield to maturity. Cheap and leveraged; can decay to zero. Symbol SPLDYT. See PT and YT explained.