Concepts

Complete-set redemption

A complete set is worth exactly $1 at resolution, so you can redeem it for $1 now — no fee, no counterparty, no price impact.

A complete set is one share of every outcome in a market: YES + NO on a binary market, or all N legs of a categorical one. Exactly one outcome resolves to $1.00 and the rest to $0.00, so holding a complete set pays exactly $1 per set at resolution, whatever the result — the payout does not depend on which outcome wins.

Because that value is certain, it does not have to wait for resolution. POST /orders/merge-positions burns a complete set out of your positions and credits $1 per set to your wallet immediately.

This is a position transformation, not a trade. Nothing is priced, nothing crosses the book, and no counterparty is involved.

What the endpoint does

Call it with a market id. The service takes the minimum share count across all of that market’s outcomes, floors it to whole cents, burns that many shares from every outcome, and credits the same number of dollars.

POST /api/v1/orders/merge-positions
{ "market_id": "1e7a…" }
{
  "market_id": "1e7a…",
  "sets_merged": "60.00",
  "amount_credited": "60.00",
  "outcomes_reduced": [
    { "outcome_id": "…", "outcome_name": "YES", "shares_burned": "60.00" },
    { "outcome_id": "…", "outcome_name": "NO",  "shares_burned": "60.00" }
  ]
}

Holding 100 YES and 60 NO merges 60 sets for $60.00, leaving 40 YES and 0 NO. The remaining 40 YES is a normal directional position and is untouched.

Properties you can rely on

PropertyWhat it means
$1 per setThe credit is sets × $1.00. There is no quote and no spread — the amount is an identity, not a price.
No feeMerging is not a trade, so no maker/taker fee is charged and no fee row appears on the ledger.
No price impactOnly your positions and your wallet move. The market’s LMSR state (amm_shares) and every displayed outcome price are untouched, so merging cannot move a mark.
Cent-exactSets are floored to whole cents, so the shares burned equal the dollars paid exactly. A sub-cent remainder stays in your position.
IdempotentThe set is recomputed under lock on each call. Once merged it is gone, so a repeated call redeems 0 and credits nothing — a retry can never double-pay.
BalancedThe credit is a double-entry journal against the market settlement pool, which already holds the offsetting liability. Nothing is minted.

When there is nothing to merge

The call succeeds with sets_merged: "0.00" — it is not an error — whenever you do not hold a complete set: a position missing on any outcome, or a minimum below one cent. Partial coverage of a categorical market (three legs of a five-way race) is not a set.

A resolved or cancelled market rejects the call: there is nothing left to redeem early.

Availability

Complete-set redemption is a flagged capability (POSITION_MERGE_ENABLED). Where it is not enabled, POST /orders/merge-positions returns 404 Not Found like any route that does not exist in that environment. Check the endpoint against your target environment before building a flow around it, and treat the 404 as “not available here”, not as a failure of your request.

Merging requires the orders:write scope.