# UFC Fight Night: Arnold Allen vs. Melquizael Costa (Featherweight, Main Card)

> Polymarket binary prediction market. 100% implied probability of YES as of Sun, 17 May 2026 03:45:55 GMT. 24h change +46.5pp, 24h volume $1.5M.

**Canonical URL:** https://orrery.me/markets/ufc-arn-mel4-2026-05-16
**Polymarket source:** https://polymarket.com/event/ufc-arn-mel4-2026-05-16
**Category:** Sports
**Resolves by:** May 17, 2026
**Last fetched:** 2026-05-17T03:45:55.403Z

## Live snapshot

| Metric | Value |
|---|---|
| YES probability | **100¢** (100%) |
| Δ 1h | +31.9pp |
| Δ 24h | +46.5pp |
| Δ 1w | +37.0pp |
| 24h volume | $1.5M |
| Lifetime volume | $1.7M |
| Liquidity (orderbook depth) | $794.0K |
| Spread | 0.10pp |
| UMA status | `proposed` |

## Resolution

**Resolves by:** May 17, 2026

**Source:** https://www.ufc.com/events

**UMA status:** `proposed` — verify before treating moves as new information.

### Market description (verbatim from Polymarket)

> This market will resolve to "Arnold Allen" if Arnold Allen is officially declared the winner of the fight against Melquizael Costa at UFC Fight Night: Allen vs. Costa, scheduled for May 16, 2026.
> 
> It will resolve to "Melquizael Costa" if Melquizael Costa is officially declared the winner.
> 
> If the fight is declared a draw or technical draw, ruled a No Contest, not scored, canceled, or postponed beyond May 30, 2026, this market will resolve "50-50."
> 
> The resolution source for this market will be official information from the UFC.

## Active signals

Signals are deterministic rules with explicit confidence (0..1). They describe *why a price moved* — they are not trade recommendations and do not predict the outcome.

- **momentum** (confidence 94%): Probability moved up 46.5pp in 24h with 2.0× liquidity turnover and a tight spread.
- **resolution_risk** (confidence 65%): Expires in 0h. UMA dispute is active.

## Top holders

**Top YES holders**

- `0x4bff…fc26` — 629,643.446 shares
- `0xdb75…0252` — 101,850.936 shares
- `0x1136…0c2e` — 100,190.135 shares
- `0x9e5e…fd91` — 65,000 shares
- `0xbddf…c684` — 48,732.396 shares

**Top NO holders**

- `0x1117…3532` — 270,058.931 shares
- `0xdbad…9c95` — 175,000 shares
- `0xa38a…821d` — 104,554.08 shares
- `0x12ec…41ae` — 76,381.281 shares
- `0x23c8…f293` — 68,234.315 shares

## 7-day price-history summary

| Metric | Value |
|---|---|
| Sample count | 168 |
| Window start | 2026-05-10T04:00:04.000Z |
| Window end | 2026-05-17T03:44:05.000Z |
| Range | 53¢ → 100¢ |
| Net change | +37.0pp |

Full series available as JSON via `GET https://orrery.me/api/markets?slugs=ufc-arn-mel4-2026-05-16` — the chart on the human page is rendered from this same data.

## Cite this

```
Orrery. "UFC Fight Night: Arnold Allen vs. Melquizael Costa (Featherweight, Main Card) — 100% on Polymarket."
Retrieved 2026-05-17T03:45:55.403Z from https://orrery.me/markets/ufc-arn-mel4-2026-05-16.
```

---

*Orrery is a public, read-only intelligence terminal for prediction markets. Not affiliated with Polymarket. Not investment, legal, or tax advice. Numbers are fetched live; citation timestamp matters. See <https://orrery.me/disclaimer>.*