Best Actress Odds 2027: Polymarket vs Kalshi

Polymarket prices Julianne Moore at 62 percent to win Best Actress at the 99th Academy Awards. Kalshi's last trade on the identical question is 53 cents. A nine-point gap on the same contract is the widest disagreement anywhere on either board.

Moore was trading at 26.5 percent on 5 September, the day The Debut premiered at Telluride. She is at 62 percent three days later. That is a 35.5-point repricing in 72 hours and the largest move this market has made since it opened on 28 July 2026.

The most-traded name is not the favourite. Inde Navarrette's Obsession contract has turned over 83,942 contracts on Kalshi against Moore's 19,310, and holds 47,013 of the board's 134,328 open interest.

Kalshi runs a separate nomination market alongside the winner market. Divide one price by the other and you get a win-if-nominated figure nobody publishes: Moore 56 percent, Navarrette 22 percent, Sandra Huller 18 percent, Renate Reinsve 11 percent.

Every board here carries an overround. Polymarket's eleven named contracts sum to 102.9 percent, Kalshi's winner board to 106 cents, and Kalshi's 25-contract nomination board to 649 cents against the 500 that five nomination slots allow.

Anne Hathaway is priced at 4 cents on Kalshi and does not exist on Polymarket at all. Ruth Madeley and Virginie Efira exist on Polymarket and not on Kalshi's winner board. Neither venue is showing you the whole field.

Where the two Best Actress boards stand today, and the nine-point gap between them. What the Telluride premiere of The Debut did to Julianne Moore's price in 72 hours. Why the most heavily traded contract belongs to a 15-cent contender rather than the favourite.

Then: how Kalshi's nomination market lets you back out a win-if-nominated probability, why both boards sum past 100, how to read spreads and open interest before you trust any percentage, the calendar between now and the 14 March 2027 ceremony, and eight questions readers keep asking.

If you looked up Best Actress odds this week, you were probably handed a stale number. The most visible prediction-market write-up on this race still quotes Julianne Moore in the mid-thirties. She has not traded anywhere near there since Sunday.

There is real money behind the correction. Polymarket's Oscars 2027: Best Actress Winner event has turned over 126,649 dollars with 26,680 dollars of open interest, 18,810 of it in the last seven days. Kalshi's equivalent board has traded 190,014 contracts and carries 134,328 in open interest.

So we pulled both boards from the source rather than from anybody's summary: the Polymarket Gamma event API and the Kalshi trade API, both read at 16:15 UTC on 8 September 2026. Polymarket prices are the last trade or mid; Kalshi prices are the last trade with the live bid and ask beside them.

Contender (film) | Polymarket | Kalshi last | Kalshi bid-ask | Gap

Julianne Moore (The Debut) | 62.0% | 53c | 53-54c | +9.0

Inde Navarrette (Obsession) | 17.5% | 15c | 15-16c | +2.5

Renate Reinsve (Fjord) | 10.0% | 7c | 7-8c | +3.0

Sandra Huller (Rose) | 8.0% | 11c | 10-11c | -3.0

Anne Hathaway (The Odyssey) | not listed | 4c | 3-4c | n/a

Ruth Madeley (Being Heumann) | 2.1% | not listed | n/a | n/a

Virginie Efira (All of a Sudden) | 1.8% | not listed | n/a | n/a

Olivia Wilde (The Invite) | not listed | 2c | 1-2c | n/a

Mikey Madison (The Social Reckoning) | not listed | 2c | 1-2c | n/a

Cynthia Erivo (Prima Facie) | not listed | 2c | 0-2c | n/a

Scarlett Johansson (Paper Tiger) | 0.3% | 1c | 0-1c | -0.7

The favourite is the same on both venues and almost nothing else is. Huller is three points dearer on Kalshi; Reinsve is three points dearer on Polymarket. Those differences get called mispricing. Mostly they are two separate crowds trading two order books that never talk to each other.

The Debut, written and directed by Jesse Eisenberg, premiered at the 53rd Telluride Film Festival on 5 September 2026. Moore plays a shy New Jersey housewife who auditions for a community-theatre musical. A24 releases it in US cinemas on 11 December, and it plays Toronto next. Variety called her performance astonishing out of the premiere.

You can watch the market absorb that in near-real time. These are daily closes from the Polymarket CLOB price history for the Moore contract, which is the market's own record rather than our reconstruction of it.

Date | Moore, Polymarket close | Note

30 July 2026 | 29.5% | Market opens

10 August 2026 | 35.5% | Pre-festival high

19 August 2026 | 24.5% | Pre-festival low

4 September 2026 | 26.5% | Telluride opens

5 September 2026 | 26.5% | The Debut premieres

6 September 2026 | 34.0% | First reviews land

7 September 2026 | 60.0% | Repricing completes

8 September 2026 | 62.0% | Current

Two things are worth taking from that shape. The first is that the premiere itself moved nothing on the day; the move arrived on the 6th and 7th, once reviews were out and the trade press had filed. Festival markets do not reprice on the screening, they reprice on the write-ups, which is a 24 to 48 hour lag you can plan around.

The second is that a 35-point move on a single festival screening tells you how little the market knew beforehand. A contract that can double on one premiere was not carrying a considered probability in August. It was carrying a placeholder. Treat every price in this category before Labor Day as provisional, including the ones that look confident.

Volume follows disagreement, not correctness, and the Best Actress board is a clean demonstration. Moore is the favourite on both venues. She is nowhere near the most-traded contract on either of them.

Contender | Polymarket outcome volume | Kalshi volume (contracts) | Kalshi open interest

Inde Navarrette | $22,462 | 83,942 | 47,013

Anne Hathaway | not listed | 19,455 | 13,854

Julianne Moore | $85,847 | 19,310 | 16,767

Olivia Wilde | not listed | 11,143 | 11,043

Renate Reinsve | $12,563 | 9,581 | 5,614

Penelope Cruz | not listed | 8,864 | 6,047

Sandra Huller | $3,367 | 7,689 | 6,520

Mikey Madison | not listed | 5,826 | 5,808

Cynthia Erivo | not listed | 5,782 | 3,502

Navarrette accounts for 44 percent of everything traded on Kalshi's winner board while priced at 15 cents. The second-busiest contract belongs to Hathaway at 4 cents. Between them, two longshots have absorbed more than half the volume in a market whose favourite sits at 53.

That pattern is what a story market looks like. Obsession was shot in 26 days for 750,000 dollars, opened in US cinemas on 15 May 2026 and has taken 509.9 million dollars worldwide with a 93 percent critics' score. A first-time lead in a horror film that outgrossed its budget by more than 600 times is a compelling thing to argue about, and people are arguing about it with money.

The venues split on which story they prefer. On Polymarket, Moore alone is 68 percent of the event's volume; on Kalshi, she is 10 percent of it. Same race, same week, two crowds pointed at opposite ends of the board. If you only read one venue you are reading one crowd's opinion and mistaking it for the market's.

Kalshi lists Best Actress twice. KXOSCARACTR-27 pays out on the winner. KXOSCARNOMACTR-27 pays out on a nomination, carries 25 contracts against the winner board's 16, and has traded slightly more than the winner market at 218,626 contracts. Polymarket has no nomination market for this category at all.

The pair is more useful together than either is alone. Divide the winner price by the nomination price and you get the market's implied probability that a contender wins given that she is nominated, which is the number awards coverage argues about all season and never quantifies.

Contender | Nomination | Winner | Implied win-if-nominated

Julianne Moore | 94c | 53c | 56%

Inde Navarrette | 68c | 15c | 22%

Sandra Huller | 61c | 11c | 18%

Penelope Cruz | 11c | 2c | 18%

Anne Hathaway | 29c | 4c | 14%

Renate Reinsve | 65c | 7c | 11%

Cynthia Erivo | 23c | 2c | 9%

Mikey Madison | 24c | 2c | 8%

Olivia Wilde | 39c | 2c | 5%

Read the Reinsve row next to the Navarrette row. The market thinks Reinsve is slightly less likely than Navarrette to be nominated, 65 against 68, and half as likely to convert a nomination into a win. Fjord won the Palme d'Or at Cannes in May 2026 and Cristian Mungiu directed it, so this is not the market doubting the film. It is the market reading Best Actress as a race that rewards a certain kind of showy lead, and a restrained performance in a European moral drama is not it.

The Huller row cuts the other way. Rose won her the Silver Bear for Best Leading Performance at the Berlin Film Festival in February 2026 and is Austria's submission for Best International Feature at the 99th Academy Awards, and her 18 percent conversion sits above Reinsve's 11 despite a lower nomination price. When a contender's win-if-nominated number is high and her nomination number is soft, the risk you are taking is about the branch, not the performance.

Add Polymarket's eleven named contracts and you get 102.9 percent. Add Kalshi's sixteen winner contracts, including its explicit Tie contract, and you get 106 cents. Neither is a bug or free money. Each contract carries its own spread, the displayed number is a last trade or a mid rather than a clearing price, and two to six points of overround is ordinary friction on a market this size.

Polymarket's board looks far worse than that if you add it up naively, because 26 of its 37 contracts are unnamed placeholders labelled Actress B through Actress Z plus an Other line, all parked at 50 cents with no bids and no volume. Sum the raw board and you get roughly 1,403 percent. Those rows are scaffolding for names the market has not added yet, not contenders at even money, and any tool that scrapes the event without filtering them will produce nonsense.

The nomination board is the more interesting arithmetic. Five actresses are nominated for Best Actress, so a complete and fairly priced nomination market should sum to 500 cents. Kalshi's sums to 649. The market is collectively expecting 6.5 nominees for five slots, a 29.8 percent overround, which is what happens when a 25-name board is priced early and nobody has been forced to sell the bottom two-thirds of it.

Then there is the roster problem, which matters more than either overround. Hathaway, Wilde, Madison, Cruz, Joan Collins and Erivo are priced on Kalshi and absent from Polymarket. Madeley, Efira, Sophie Okonedo, Rachel Brosnahan, Michelle Williams and Lea Seydoux are priced on Polymarket and absent from Kalshi's winner board. Before you read any percentage as a probability, count the names on the board and compare them with the field you actually believe in. It takes twenty seconds and it catches errors that staring at a price chart never will.

A price with nothing behind it is a rumour with a decimal point. These are the live spreads on both venues, and they vary by more than an order of magnitude across the same board.

Contender | Polymarket bid-ask | PM spread | Kalshi bid-ask | Kalshi spread

Julianne Moore | 61-63c | 2.0 | 53-54c | 1.0

Inde Navarrette | 17-18c | 1.0 | 15-16c | 1.0

Renate Reinsve | 9-11c | 2.0 | 7-8c | 1.0

Sandra Huller | 6.9-9.0c | 2.1 | 10-11c | 1.0

Virginie Efira | 0.3-3.2c | 2.9 | not listed | n/a

Ruth Madeley | 0.4-3.7c | 3.3 | not listed | n/a

The top four contracts on either venue are tight enough to take seriously. Below them, Polymarket's longshots quote a bid at a third of a cent against an ask above three, which is a spread ten times the width of the price itself. A contract quoted 0.4 to 3.7 does not have a 2.1 percent probability. It has a range, and the mid is a convenience rather than a belief.

Kalshi's nomination board is worse on this measure than its winner board. Erivo is quoted 17 to 45 there, Collins 3 to 17 and Daisy Edgar-Jones 2 to 9, so several of the conversion numbers in the previous section rest on a last trade rather than a live two-sided market. We flagged the ones worth trusting: Moore, Navarrette, Huller and Reinsve all have real books on both sides.

One more artifact worth naming. Reinsve closed at 13.5 percent every day from 7 August to 6 September, printed 4.5 on 7 September, and is back at 10.0 today. A single trade through a thin book can move a displayed price by nine points and mean nothing. Check the volume column before you conclude that a contender collapsed overnight. Our guide to reading Polymarket volume and liquidity goes further into this.

This race is six months from resolution and most of its information has not arrived yet. The 99th Academy Awards will be handed out on Sunday 14 March 2027 at the Dolby Theatre, broadcast on ABC. Here is everything between now and then that the market has to price.

Date | Event

2-12 September 2026 | 83rd Venice International Film Festival

4-7 September 2026 | 53rd Telluride Film Festival (The Debut premiered on the 5th)

10-20 September 2026 | 51st Toronto International Film Festival

11 December 2026 | The Debut opens in US cinemas via A24

15 December 2026 | 99th Oscars shortlists announced

11-15 January 2027 | Nominations voting

21 January 2027 | Nominations announced

16 February 2027 | Nominees luncheon

25 February - 4 March 2027 | Final voting

14 March 2027 | 99th Academy Awards ceremony

The single largest scheduled repricing is 21 January. On that morning every contender who misses the five-name list goes to zero, and both venues resolve their nomination contracts outright. Kalshi's rules send an unnominated actress's winner contract to No the moment the list is read, and Polymarket's event description says the same thing.

Between now and then the guild awards, the critics' prizes and the Golden Globes will each move the board, usually less than people expect. Last cycle the market barely flinched at nominations morning: the eventual Best Picture winner sat between 68 and 77 percent from early January through the ceremony, and a record 16-nomination haul for a rival moved it by almost nothing. Jessie Buckley took Best Actress at the 98th ceremony on 15 March 2026 for Hamnet as a heavy favourite. Favourites in this category do usually win, which is exactly why a 62 percent price is worth arguing about rather than accepting.

Every number in this article came from a public API you can call yourself, and we would rather you did. The Polymarket Gamma endpoint for this event and the Kalshi markets endpoint for both tickers are linked in the sources below, and both are open, keyless and free.

If you want the rest of the season rather than one category, the ScreenOdds awards hub carries live Oscars, Emmys, Grammys and Tonys context, and our Oscars hub tracks this cycle specifically. Our Best Actor odds guide is the companion piece to this one, and the Best Picture market page shows how a season-long contract behaves across a full awards run.

A note on what this page is and is not. ScreenOdds is an odds-research site: we publish prices, volumes and the arithmetic behind them, and some links on this site are affiliate links to prediction-market venues. Nothing here is financial or betting advice, prediction-market contracts can lose their full value, and availability differs by jurisdiction. Polymarket restricts trading for US persons; Kalshi is a CFTC-regulated designated contract market with its own eligibility rules. Check what applies where you are before you act on any number on this page.

We re-read both boards whenever a contender moves more than a few points, and this article carries the timestamp of its last snapshot at the top of the sources block. If Moore's 62 and Kalshi's 53 have converged by the time you read this, that is the market working, not the article ageing badly.