Oscar statuettes in various stages of the plating process are displayed at the R.S. Owens factory in Chicago, Illinois, U.S. Photographer: TIM BOYLE/Bloomberg
INTERNATIONAL - The race for Hollywood’s biggest prize, the Oscar for best picture, is the closest in years, with “The Shape of Water’’ and “Three Billboards Outside Ebbing, Missouri’’ virtually tied, according to oddsmakers and trackers. They see less chance for “Get Out,’’ “Lady Bird” and “Dunkirk” unless the motion picture academy’s quirky voting system throws a curve.

“It’s incredibly tight this year,” said Jessica Bridge, a spokeswoman for the U.K. betting group Ladbrokes Plc. “Three Billboards” is the favorite at 10 to 11, with “The Shape of Water” at 13 to 8, she said. The rest are 10 to 1 or higher. “Both films have occupied the top spot at some point since the start of the year,” she said.

Bettors have a good record predicting the winner. First or second favorites have won every year since 2006, according to the company. Even last year’s surprise “Moonlight” was the second favorite at 6 to 1. But before you go filling out your Oscar predictions or counting your office pool winnings, there are other issues to consider, such as changes in Oscar rules and earlier awards races where the favorites fell short.

“The pundits are all perplexed on how to size up the race this year because there are five films that have a realistic chance to win,’’ said Tom O’Neil, editor of the awards website Gold Derby, which surveys awards experts and journalists.

The two leading films have faced criticism. Guillermo Del Toro, who wrote and directed the 21st Century Fox Inc. film “The Shape of Water,’’ was accused of plagiarizing his sci-fi tale about a mute women who falls in love with a reptilian humanoid. He has denied the claim.

Late Controversies

But just after Oscar voting closing on Feb. 27, the film fell behind “Three Billboards,’’ according to Gold Derby. And as of late Thursday, “Three Billboards,” about a mom who takes the police to task for failing to catch her daughter’s killer, had a 38.5 percent chance of winning, compared with 30.3 percent for Del Toro’s film, according to Gold Derby.

“Three Billboards,” which is also from Fox, has drawn criticism, too, from film and cultural critics who have spoken out about the film’s plot, which features a racist police officer.

Rising in the odds has been “Get Out,’’ widely praised for writer and director Jordan Peele’s use of the horror genre to create an unflinching portrayal of race relations. The film from Comcast Corp.’s Universal Pictures has a 20 percent chance of winning, according to Gold Derby.

Preferential Ballot

The academy introduced a so-called preferential ballot in 2009, which asks the organization’s 7,000-plus members to rank films rather than pick a winner. That has tended to result in winners that are more widely liked, rather than deeply loved by a smaller group.

“Ever since, we have had upset after ambush after shock,’’ said O’Neil.

Last year “La La Land’’ had a more than 80 percent chance of winning, according to Ladbrokes, but ultimately was toppled by “Moonlight.’’

The academy has also changed membership rules and increased invitations to minorities to alter its largely white, male demographics. That was done in response to the online campaign called #oscarssowhite, which highlighted the lack of diversity in the nominations.

Guild Awards

Also driving odds calculations are the results from guild awards that provide clues to how the academy members will vote. “The Shape of Water’’ won the prizes for directing from the Directors Guild and the British Film Academy, whose members overlap in part with the film academy. Their choices often point to the ultimate best picture winner.

But “Three Billboards’’ took home the top prize at the Screen Actors Guild, and with actors being the largest voting bloc for Oscars, that film was suddenly looking like a sure thing. “Get Out’’ got a boost for taking the top prize from the Writers Guild. It’s nominated for best screenplay, which also correlates highly with best picture.

The real winners, of course, will be the studios, which will enjoy a jump in box-office sales or purchases if their picture wins. From that standpoint, Fox looks to be in good shape with two of the five pictures that look to be in the best position. The award could also end up in the hands of Time Warner Inc.’s Warner Bros. division, which made “Dunkirk,” or A24, the independent distributor behind the teen coming of age tale “Lady Bird.”

O’Neil says the odds in effect point to a split at the top -- a five-way toss up. “You could talk yourself into any one of those scenarios,’’ he said.