Crypto Gloss

Principal Tokens

Principal Tokens (PT) are the fixed-income component of Pendle Finance’s yield stripping mechanism — one of two tokens produced when a yield-bearing token (stETH, weETH, aUSDC) is split on Pendle: PT (the principal claim) and YT (the yield claim). A PT represents a simple contractual right: at the token’s fixed maturity date, 1 PT redeems for exactly 1 unit of the underlying yield-bearing token — regardless of what yield rates were during the period, and regardless of what price was paid for the PT. Because PT always redeems at par (1:1 at maturity) but currently trades below par (at a discount), the discount implies a fixed annual yield rate — just as a zero-coupon bond trading at 95 cents on the dollar for a 1-year bond implies a 5.26% annual yield. This makes PT the DeFi equivalent of a zero-coupon bond: a simple, predictable instrument that transforms variable-rate staking or lending yield into a fixed rate locked in at purchase time. Investors who buy PT accept giving up their variable yield exposure (which goes to YT holders) in exchange for certainty that their investment will return a known fixed rate regardless of what staking yields do over the period. PT-weETH (backed by Ether.fi’s liquid restaking token) became the largest PT market in DeFi in 2024, with billions in notional outstanding.

Key Facts

  • Protocol: Pendle Finance (primary; other protocols experimenting with similar mechanisms)
  • Mechanism: Yield bearing token split into PT (principal) + YT (yield)
  • Redemption: 1 PT = 1 underlying SY token at maturity (guaranteed by Pendle smart contract)
  • Price today: Always < 1 underlying (discount to par implies fixed yield)
  • Implied yield: (1 – PT price) / PT price × (365 / days to maturity) = annualized fixed yield
  • Risk profile: Lower than YT; primary risks: protocol risk + underlying asset risk
  • DeFi status: Can be used as collateral in some protocols (MorphoBlue, certain Aave installations)
  • Traditional analogy: Zero-coupon bond; Treasury principal STRIP

PT Pricing and Implied Yield

Formula:

Implied fixed yield = ((1 − P_PT) ÷ P_PT) × (365 ÷ days to maturity)

Where:

  • $P_{PT}$ = current price of PT (in units of underlying)
  • $d$ = days remaining to maturity

Example:

  • PT-weETH priced at 0.95 weETH, 180 days to maturity
  • Implied yield = (1 – 0.95) / 0.95 × (365/180) = 0.053 × 2.028 = 10.7% APY
  • Interpretation: buying PT-weETH at 0.95 today = receiving 1 weETH at maturity = equivalent to earning 10.7% fixed APY

PT price factors:

  • Market’s expected yield of underlying (higher expected yield → YT is more valuable → PT is cheaper → higher implied fixed yield)
  • Time to maturity (more time → larger discount possible)
  • Supply/demand (points speculation can push YT demand → PT becomes very cheap = very high implied fixed yield)

Practical market range (2024):

  • stETH PT implied yield: 4-6% (close to actual stETH yield of ~4-5%)
  • weETH PT implied yield: 6-12% (higher because: YT buyers pay premium for EigenLayer points exposure; causes PT price to be lower than stETH equivalent)

PT as a DeFi Primitive

The following sections cover this in detail.

PT is a Zero-Coupon Bond

Zero-coupon bond (traditional finance):

  • Bond issued at discount, no periodic interest, redeems at par
  • Example: $950 today → $1,000 in 1 year = 5.26% yield
  • Institutional use: duration management, liability matching

PT-stETH (DeFi):

  • Token purchased at discount; no periodic yield (all yield goes to YT holders); redeems 1:1 at maturity
  • Example: 0.95 stETH today → 1 stETH in 1 year = 5.26% yield in stETH (not USD)
  • DeFi use: fixed ETH yield, hedging staking yield variance, stable capital deployment

PT as Collateral

Some DeFi protocols accept PT as collateral:

  • MorphoBlue: PT-weETH as collateral in specific curator vaults
  • Collateral logic: PT has known maturity value (1 underlying); lending protocol: liquidates before maturity if needed
  • LTV: lower than underlying (uncertain marketability near maturity)
  • Advanced strategy: buy PT → deposit as collateral → borrow to buy more PT (fixed yield leverage)

PT Risk Profile vs. Alternatives

Instrument Risk Yield
Native ETH Lowest None
stETH Low Variable (~4-5%)
PT-stETH Low (+ Pendle risk) Fixed (~4-6%)
YT-stETH High Variable + leveraged
wstETH on Aave (collateral loop) Medium Variable (~6-8% levered)

PT specific risks:

  • Pendle smart contract risk: Pendle: multiple audits (OpenZeppelin, Spearbit, Cantina); no major exploit; but: any smart contract can have bugs
  • Underlying asset risk: PT-stETH: underlying stETH must be redeemable; Lido smart contract risk; validator slashing risk (minor)
  • Liquidity risk: PT before maturity: must sell on Pendle AMM; if Pendle AMM: illiquid (large PT position → price impact)
  • Extension risk: If Pendle delays/prevents maturity redemption (governance change) — mitigated by immutable core contracts

Related Terms

Sources

  1. “PT Markets: How Pendle’s Principal Tokens Create Fixed-Rate ETH Yield Instruments” — Pendle Finance / Principal Token Research (2024). Technical analysis of how PT markets function on Pendle — examining the specific AMM mechanics that price PTs (time-value-of-money incorporated into Pendle’s custom AMM; difference from standard constant-product AMM), the empirical relationship between PT implied yields and actual LST yields over time, how the EigenLayer points narrative caused PT weETH yields to spike above underlying staking yield, and whether PT markets are efficient (implied fixed yields: accurate predictors of future actual yields).
  1. “Zero-Coupon ETH: How PT-stETH Changes Duration Management for ETH-Denominated Portfolios” — DeFi Research / Fixed Income Analysis (2024). Analysis of how PT tokens enable DeFi-native “duration management” for ETH-denominated portfolios — examining how purchasers of PT-stETH can construct ETH-denominated bond portfolios with specific maturities (analogous to how pension funds construct bond ladders), the theoretical “ETH yield curve” implied by cross-maturity PT prices, and whether institutional ETH holders could practically use PT-stETH for ETH liability matching strategies similar to pension funds using Treasury STRIPS for dollar liability matching.
  1. “PT Collateral in DeFi Lending: MorphoBlue’s PT-weETH Vaults and Fixed-Yield Leverage” — Morpho Labs / PT Collateral Research (2024). Technical analysis of MorphoBlue’s integration of PT tokens as collateral — examining the specific vault architecture (curator vault accepting PT-weETH as collateral; lends against PT at conservative LTV; liquidator setup for PT near-maturity scenarios), the innovative nature of lending against time-decaying assets (PT: approaching par at maturity but discounted today; collateral value: increasing over time if holding to maturity → unusual collateral type), and what “PT leverage” strategies (borrow against PT; buy more PT; collect fixed yield on leveraged amount) look like in practice.
  1. “Fixed Yield vs. Variable Yield: Survey of Who Buys PT and Why in the DeFi Ecosystem” — On-Chain Analytics / Pendle User Analysis (2024). On-chain behavioral analysis of PT buyers on Pendle — examining wallet behavior (who buys PT vs. YT: wallet size, holding duration, protocol interaction patterns), the ratio of sophisticated vs. retail PT buyers, whether PT buying is correlated with specific market conditions (high volatility → more PT demand for certainty; bull market → more YT demand for upside), and what the typical PT investment duration looks like (do most PT buyers hold to maturity or sell early on AMM?).
  1. “PT Implied Yields vs. On-Chain Borrowing Rates: Is Fixed Yield via PT Better than Stablecoin USDC Lending Rates?” — DeFi Research (2024). Comparison of PT-implied fixed yields vs. alternative DeFi fixed/variable yield sources — examining whether PT-weETH’s 8-12% implied fixed yield (during peak restaking speculation) was superior to USDC lending on Aave (~5-8%), ETH yield on Compound (~variable 2-5%), or stETH holding (~4-5%), and how the denomination mismatch (PT: ETH-denominated; Aave USDC: dollar-denominated) complicates direct comparison for investors with different base currency preferences.