Should your venue adopt this?
Most venues should not, and it is more useful to start there.
This mechanism buys one thing — a settlement rule that pays for early risk-bearing and needs no market maker — and pays for it with three: no exit, no live late price, no hedging. If you need any of those three, no amount of tuning gets them back, because they are not missing features. They are the consideration.
So: the disqualifications first.
Do not adopt it if…
1. Your users trade in and out
Scalping, taking profit early, cutting a loser, rolling a position — all of it is gone. There is no exit in the mechanism. Positions are transferable in principle, but nothing in the rule provides a buyer, and the layer that would (§8) is a measured bound rather than a shipped design even in the paper's own account of it.
This is the single most common disqualification and the one most often rationalized away. Do not.
2. The displayed price is your product
If people come to you for the number — if your market page's headline is "73%" and that number is the thing being consumed, syndicated, or cited — this mechanism degrades exactly that number, on purpose, and the degradation is measured:
| Brier score, final 5% | |
|---|---|
| classic + lock (deployed baseline) | 0.150 |
| vested | 0.174 |
The mean absolute gap to true probability, |q − p|, is weakly worse in every phase, not just the last. And §7's two-sided band shows the ratio is not a probability at all in a fast-growing market — the two implied prices need not sum to one.
3. You serve hedgers
A party with real exposure wanting protection late faces +0% on a win and −100% on a loss. In a book or an LMSR they buy at 0.93 and are covered. The paper's prescription for hedging-relevant markets is λ well below 1 — but interior λ voids the creation floor (measured worst case −16.8% at λ = 0.5) and re-opens the lock window in proportion to 1 − λ. A hedging market under this family is an operator-seeded or floor-waived market, and the reason to adopt has evaporated.
4. Your markets are long-dated
Capital is locked from entry to resolution. At 4% and six months, the 2% carry hurdle is the same order as the entire observed late-tercile win-conditional yield (median 2.7%) and exceeds the median final-decile winner's post-fee return. It applies to the seed too, which turns the nominal floor into a real loss on slow markets.
The paper's own summary: λ = 1 is a short-horizon mechanism.
5. Your markets are mostly n-way, and you want a finite κ
With three or more outcomes, one stake of S(κ − n + 1) renders the market permanently un-enterable on every outcome — an absorbing state with no in-mechanism recovery, reachable at any point in the market's life. At the reference parameters (κ = 9, n = 3, $50 seed) the trigger is $350.
This one is survivable: run n-way markets at large or unbounded κ, where soundness rests on the seed and scale-invariance instead. But if you had a specific reason to want a tight leverage cap on multi-outcome markets, you cannot have it. Details.
6. You are a regulated exchange with a filed rulebook
Changing how contracts settle is a regulatory matter, and the venues in that position generally run books at the head of the market, where the cold-start problem they would be solving does not exist.
Adopt it if…
1. You already run classic parimutuel pools
The strongest case in the paper, and it is strong because there is almost nothing to change. Same pot, same conservation, same cold start, same lack of a market maker. λ = 0 is the rule you already run, so the dial is a migration path rather than a rebuild, and κ is published policy like a fee table.
You have already paid for cold start. You are paying instead at the other end, through the lock window, where the free-ride you are defending against measures +25.27% pre-fee. That window deletes as an identity. The full case.
2. Your creators fund per-market liquidity today
If you are Manifold-shaped — creators capitalize their own markets and absorb the loss — you are offering the same person the same slot with a floor instead of an expected loss. Worst case over 40,000 markets: +10.9% pre-fee, +8.6% after a 2% fee, 0 markets settling negative. Against a classic straddle's −46.8% worst case and 83.4% negative.
Your users already accept per-market capital as normal, which is the hard part of the sell, and you skip it.
3. Your bottleneck is market count, not market depth
If the reason you have 400 markets instead of 40,000 is that each one needs someone's attention, this is the mechanism aimed at your problem. Seeding is a legible job: a floor, a closed-form position value, and economics that depend on forecastable quantities (flow volume and balance) rather than on out-quoting a professional. The long-tail argument.
4. You run short recurring rounds
Fifteen-minute price-direction rounds, hourly settlements, that shape. No book can form, no LP will fund a curve, and no position market can form inside the round either — so you were never getting exit anyway, and the mechanism's biggest cost is one you had already paid.
The paper puts these markets third in its adoption order, with one requirement attached: a venue-side RFQ cash-out at a published spread as the degenerate secondary layer, whose quote must never be a mechanical function of the pool ratio.
The three questions that decide it
If you want to skip the lists:
1. Can your users currently sell before resolution, and would they mind stopping? If yes and yes — stop here.
2. Is your displayed probability consumed as a probability by anyone outside your product? If yes — you are paying 0.174 against 0.150 for something you sell. Probably stop.
3. Is your binding constraint "we can't make enough markets" or "our markets aren't deep enough"? Only the first one is the problem this solves.
Partial adoption is the normal answer
Nobody has to flip a venue. The dial exists precisely so this can be done per market class:
| your market class | setting | rationale |
|---|---|---|
| short recurring rounds | λ = 1, κ = 9 | no exit was available anyway; lock window deleted |
| binary event markets, days-to-weeks | λ = 1 or 0.75 | check carry against duration |
| hedging-relevant markets | λ well below 1 | accept the floor is void |
| n-way ladders | λ = 1, κ unbounded | P9c is absorbing |
| long-dated markets | leave as they are | carry eats the yield |
| your deep flagship markets | leave as they are | they already work |
The order of adoption
If you decide yes, the paper prescribes an order, least-recoverable risk last (§15):
- Paper first. Flow-vesting settlement in a paper-money twin, behind your existing payout authority.
- The secondary layer, where it can exist. For markets long enough for a position market to form, ship transferable positions and the cash-out affordance before real money — §8 is a precondition, not a follow-up.
- Real money where P4 bites, with the degenerate secondary layer built in: short recurring markets at λ = 1 plus the RFQ cash-out.
- Creator-seeded permissionless creation, with vintage 0 as the first rung of the resolution bond and §12's timeout-forfeiture and scaling-bond rules in place from day one.
Step 2 is the one people skip, and it is the one the paper is most insistent about.
What you owe your users if you do it
Three disclosures, none optional:
- The displayed ratio is not a probability. Say so on the surface, not in a FAQ.
- There is no exit unless you built one. If you built an RFQ vault, publish its spread; if you did not, say there is no exit.
- The published parameters. κ, λ, the fee schedule and its base, the minimum stake, and the residue owner are all venue policy, and the paper says they should be committed on-chain per market, before it opens.
And one more, from §14, which venues will not enjoy: featuring a market transfers expected value toward its earliest vintages. If you promote markets, you are moving value to whoever seeded them, and that should be disclosed rather than discovered.