What Is a Fork?

A fork is Augur’s resolution method of last resort. It begins when a market disagreement survives the ordinary reporting and dispute process and a dispute bond reaches the protocol’s fork threshold. The protocol then makes outcome-specific child universes available so REP holders can commit to the outcome they believe is correct; each child is created only when migration first targets that outcome.

This page is evergreen protocol education. It does not announce a live fork, set a migration deadline, or tell anyone to move REP.

New to this topic? This path assumes a basic familiarity with prediction markets and Augur’s reporting cycle. It starts with the fork trigger, then explains disputes, general migration mechanics, preparedness, and the boundary between protocol education and historical event material.

Learning outcomes

By the end of this path, you should be able to:

distinguish an initial report, a dispute, and a fork;
explain why dispute bonds escalate and what the fork threshold means;
describe one-way REP migration without treating it as a current action;
read the site’s fork monitor as a measurement of protocol state, not a probability forecast; and
separate reusable mechanics from facts about the completed Moon Fork.

The Fork learning path

The lessons are ordered so each one supplies context for the next:

What Is a Fork? — the trigger, lifecycle, and vocabulary.
How Disputes & Bonds Work — the escalation mechanism that can lead to a fork.
How Fork Migration Works — general child-universe and migration mechanics.
What To Do Around Fork Risk — preparedness for a possible future fork, not an active-event checklist.
The Moon Fork — the completed event as a dated, evidence-based case study.
Moon Fork Migration Record — the existing historical procedure, retained for research and troubleshooting rather than current instructions.

Key terms

REP — Augur v2’s reputation token. It is used in reporting and disputes; it is not the currency used to trade market shares.

Tentative outcome — The outcome currently proposed by the reporting process. It can change when a dispute succeeds.

Dispute bond — The protocol-calculated amount of REP that must be filled to successfully dispute a tentative outcome. A bond can be crowdsourced by multiple participants.

Universe — An Augur protocol context containing markets and a REP token. A fork makes a child universe available for each possible outcome, including Invalid; the child is created when migration first targets that outcome.

Theoretical REP — The supply basis used by the protocol for percentage thresholds. The genesis-universe reference is 11,000,000 REP, so 2.5% is 275,000 REP; a live deployment’s configured value is authoritative.

What the monitor means

The fork monitor measures progress through an observed dispute escalation path:

(Current funded dispute round ÷ Estimated total rounds) × 100 = Round progress

The estimate is derived from the observed bond trajectory. It is a display signal for how far escalation has progressed; it is not a probability that a fork will happen, a judgment about which outcome is true, or evidence that migration is open.

Fork lifecycle in brief

A dispute reaches the threshold. A successfully filled dispute bond of at least 2.5% of theoretical REP puts the market into the fork state. The 275,000 REP figure is the genesis-universe reference, not a universal substitute for the deployed protocol value.
Child universes become available. There is a possible child for each outcome of the forking market, including Invalid. A child universe and its REP token are created only when migration first targets that outcome.
The parent universe is locked. No new markets or REP staking begin there. Disputes in other non-finalized markets are put on hold, although trading can continue and those markets cannot finalize until the fork period ends.
REP can be migrated once. Holders choose a child universe, and that choice cannot be reversed or moved to a sibling universe. The fork period lasts up to 60 days under the Augur v2 reference mechanics.
The fork resolves. The child receiving the most migrated REP by the end of the forking period becomes the winning universe, and its corresponding outcome becomes the forking market’s final outcome.
The result becomes historical protocol state. Non-finalized markets can continue only in the winning universe. Event-specific addresses, totals, deadlines, and observations belong in a case study or historical record, not in this lesson.

Continue

Continue to How Disputes & Bonds Work →.
Then read How Fork Migration Works → for the general mechanics.
Use What To Do Around Fork Risk → for future-oriented preparation.
Read The Moon Fork → for the completed event and its evidence.
The Moon Fork Migration Record is preserved at its existing URL as historical material.

Protocol basis

This explanation follows the maintained Augur v2 reference and the version-controlled implementation: the canonical Augur v2 whitepaper, Universe.sol, and ReputationToken.sol.