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Supracoin vs Stablecoin

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PXS promises no price. The mechanisms compared here run on mainnet; supracoin is the PXS design notes' name for the category they place PXS in. This page compares mechanisms and states no legal classification. Last checked 2026-10-06.

A common question about PXS is whether it is a stablecoin. The PXS design notes answer that the question starts from the wrong ruler: it measures PXS against a fiat currency, when PXS is built to stand beside one. This page sets out that answer through the mechanisms, so that a reader can check it: what a defended unit relies on, what PXS has instead, and where the risk ends up.

What PXS promises

PXS promises no price. It has no peg, cannot be redeemed for money and pays no interest, and no one stands behind its value. A PXS converts into newly created PIXA at the median of the witnesses' feeds, less the haircut. Everything below follows from these facts, not from the name given to them.

What a defended unit relies on

A unit aimed at one unit of a fiat currency usually combines three mechanisms:

  1. A target price that it defends: one unit of the currency.
  2. Redemption at that price, by an issuer, typically on demand.
  3. A reserve that the issuer holds to pay redemptions.

When the reserve or the issuer gives way, the unit breaks from its target. PXS has none of the three:

Aspect A unit aimed at a fiat currency PXS
Target price one unit of the currency, defended none: what a conversion delivers varies, and falls under stress
Redemption at par, from the issuer none: the protocol converts PXS into PIXA at the median feed, less the haircut
Reserve held by the issuer to pay redemptions none: the PIXA a conversion pays is created for it
Where the risk sits in the reserve and the issuer's solvency in the honesty of the witnesses' feeds and in PIXA's market value; PIXA holders carry the dilution, within the haircut's limit

Money and currency

The design notes borrow two ideas from writers on money.

  • Currency is not money. In Mike Maloney's distinction, a currency is a medium of exchange and a unit of account: portable, durable, divisible and fungible. Money is all of that and also a store of value over long periods. On this view, a unit tied to a fiat currency is currency, not money.
  • Money pays no yield. Alan Hibbard argues that money pays no yield because it is a store of value rather than a risk position; yield comes from taking risk. The design gives this as the reason PXS pays no interest.

The design places PXS at neither pole. It orients toward the property that separates money from currency, purchasing power, and declines money's guarantee. Orientation is not a promise: a PXS can deliver more or less than a Big Mac's worth of PIXA, and under stress it delivers less.

Four kinds of monetary unit

Aspect Fiat currency Commodity money Stablecoin Supracoin (PXS)
Reference the issuing state's decision its own substance a fiat currency a Big Mac, read by the witnesses
What it rests on confidence in the issuer the commodity itself a reserve held by the issuer nothing set aside: it settles in PIXA that each conversion creates
Behaviour of its value loses purchasing power as its supply grows follows the commodity follows its currency while the reserve holds follows what the feed and PIXA's market make of it, less the haircut under stress
Issuer a central bank none the issuer none; created by protocol rules
Typical failure debasement loss or theft the reserve or the issuer fails, and the unit breaks from its reference PIXA loses value, and conversions deliver less

Adapted from the design notes, figure 6. The last column describes the chain as it runs today.

What a holder holds

The design's image is a chain of claim checks. A unit referenced to a fiat currency is a claim on an issuer's reserve, and the reserve is usually a claim on a bank or a state. Each link is a promise resting on the one before, and a failure anywhere travels forward along the chain.

A PXS is not on that chain. It is a balance that the protocol converts into PIXA, which it creates for the purpose. There is no counterparty to fail and no reserve to run on. That does not make PXS independent:

  • The conversion depends on the feed, whose median on 2026-11-03 still rested on a placeholder price for PIXA (Oracle and Price Feed).
  • What the PIXA is worth depends on PIXA's market, which is one thin order book.
  • Conversions dilute PIXA holders. The haircut limits how fast (Haircut, Corridor and Settlement).

The design notes put it in one line: "Risk is relocated, not removed."

The design's test, applied to the chain

The design notes propose a test. If the four terms Oracle, Atlas, Supra and Macro describe a unit completely, and the four terms peg, reserve, defence and issuer cannot describe it at all, the unit is a supracoin and not a stablecoin. Applied to the running chain:

Term On the Pixa chain
Peg None. No code targets a PXS price. The feed is an input to conversions, not a target.
Reserve None. The treasury's 249,266.219 PXS are PXS, spent on proposals, not assets held behind PXS.
Defence None. The chain never buys or sells PXS. When PXS grows large, it stops printing at a debt ratio of 20%, then cuts what each PXS delivers above 30% (thresholds). It adjusts; it does not defend.
Issuer None in the protocol. PXS is created by fixed rules: author rewards, the fund's share of issuance and conversions. The 245,098.039 PXS seeded at genesis were set by the chain's code. No account can change these rules alone: a change needs a hardfork that the witnesses adopt, and on 2026-10-05 six accounts, five of them with stake, had elected all nine witnesses (Decentralization and Safeguards).

The protocol has no issuer; who elects the witnesses decides how far that holds in practice.

What the word does not change

  • Safety. Calling PXS a supracoin makes it no safer. What PXS is follows from its mechanism, not from its name (Style Guide, statement 4).
  • Where the risk goes. Risk is moved, not removed. It sits with PXS holders, who carry the feed's errors, the haircut and the need to find a buyer for the PIXA they receive; with PIXA holders, who carry the dilution; and with the honesty of the witnesses.
  • The reference. A Big Mac is a direction, never a destination. Under stress, a PXS settles for less than the reference names.
  • Legal status. This page compares mechanisms. It states no legal classification of PXS or of any other token.

Inherited → changed

Aspect Steem / Hive Pixa
How the unit was described "Steem Dollars": a convertible note aimed at one US dollar a supracoin that promises no price
Reference one US dollar one Big Mac
Interest yes; on Hive, in savings only none
Under stress the debt limit cuts what a conversion delivers, as on Steem in 2019 the same rule, presented as the mechanism itself

Sources