Onchain Atlas

Seigniorage Shares

A stablecoin design where a second token absorbs the profits and losses of keeping the stablecoin at its peg.

Also called: algorithmic stablecoin shares · bond-share stablecoin model

What it is

Seigniorage shares is a three-token (or two-token) system for building a stablecoin without full collateral backing. Instead of holding dollars or crypto assets 1:1, the system prints new stablecoins when the price is above target and gives that new supply to holders of a separate "share" token, and it sells discounted "bond" tokens (redeemable later) to shrink supply when the price is below target. The share token functions like equity in a central bank: it absorbs the profit ("seigniorage") of expansion but has no guaranteed value when the system contracts.

How it works

  1. An oracle or on-chain price feed reports the stablecoin's market price against its $1 target.
  2. If the price is above $1, the protocol mints new stablecoins according to a rule (e.g., proportional to the price deviation and total supply).
  3. New stablecoin supply is distributed to whoever stakes or holds the share token, diluting price back toward the peg while rewarding share holders.
  4. If the price is below $1, the protocol doesn't mint; instead it sells bond tokens at a discount to the stablecoin (e.g., buy a bond for $0.90, redeemable for $1 stablecoin later), pulling stablecoins out of circulation to reduce supply and support the price.
  5. Bonds are only redeemed once the price recovers above $1 and new seigniorage is available, and typically redeem in the order issued or with an expiry.
  6. Share-token holders are the residual claimants: they profit in expansions but hold a token with no cash-flow floor and no claim on collateral during sustained contractions.

Why designers use it

  • Avoids locking up large amounts of collateral, in theory letting the stablecoin scale with demand rather than reserves.
  • Creates an incentive-aligned participant (the share holder) whose job is to absorb volatility so the stablecoin itself can stay stable.
  • Lets the protocol expand supply "for free" during growth, funding future defense of the peg via bond sales.

Failure modes

  • If price stays below peg for a long time, bonds pile up undeliverable and confidence collapses — this is the classic death spiral seen in several algorithmic stablecoins.
  • Share-token value depends entirely on expectations of future expansion; once the market doubts recovery, shares can go to near zero, removing the very buyer of last resort the system needs.
  • Bond mechanics only work if new buyers keep showing up to buy discounted bonds; in a falling market, no rational buyer wants a bond redeemable in a token that keeps falling.
  • Reflexivity: the mechanism that's supposed to restore the peg (selling bonds, minting to shares) itself depends on the peg being credible, so failures tend to be sudden and total rather than gradual.

What to check before using it

  • Model the bond-redemption backlog under a sustained below-peg scenario — is there an expiry or cap, and what happens if bonds never clear?
  • Check what backs the share token's value beyond future seigniorage — is there any collateral floor at all?
  • Look at the minting/bond-issuance formula's sensitivity: does a small price deviation cause outsized dilution or bond discounts?
  • Examine historical stress tests or the closest real-world analog (most algorithmic stablecoins of this design have failed) before assuming this time is different.

Experiments that used it · 3

Shown oldest first, so you can watch the design evolve.

Basis
A venture-backed algorithmic 'central bank' stablecoin that raised $133M but voluntarily shut down and returned all capital in 2018 before launch, citing regulatory constraints on its bond and share tokens.
2018 abandoned
Basis Cash
A seigniorage-shares algorithmic stablecoin that revived the shut-down Basis (Basecoin) design on Ethereum using a three-token bond/share mechanism to hold a $1 peg.
2020 failed
Dynamic Set Dollar
A faster, more aggressive fork of Empty Set Dollar whose uncollateralized rebase-and-coupon stablecoin ballooned to ~$300M in weeks, lost its $1 peg within a month, and never recovered despite a v2 redesign.
2020 failed