This year marks the first Olympics for legalized sports betting across the United States. Why has a potential boon made bookies nervous?

These are the first Games since the Supreme Court in 2018 opened the floodgates for expansion of sports betting in the United States, so we think a word should be added to the revered Olympic motto.

Citius, Altius, Fortius ... Operimentum: Faster, Higher, Stronger ... Cover.

DraftKings in New Jersey has German rower Oliver Zeidler favored to win gold in single sculls rowing at +120. There are lines on team handball, men’s windsurfing and women’s water polo, in which the U.S. is a heavy favorite. Just about everything is on the board, even épée.

“One thing about bookmakers,” said Johnny Avello, DraftKings’ director of operations, “is that bookmakers can make a line on anything. Just need a little bit of data.”

Most betting on the Olympics in the United States will be on the mainstream sports: basketball, soccer, golf, etc. But, for many houses, gymnastics is not on the board. The judging is too subjective and many of the athletes are under 18 years old, which regulators frown on.

Turns out there is a slice of morality even in sports betting. Just don’t tell that to the sharps who clean up on the Spelling Bee.

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There will be similar dancing between players and oddsmakers over the next couple of weeks, especially with the obscure sports. A couple of bookies are nervous.

“We’re so confident in our line for Game 6 of the NBA Finals, whereas fencing and water polo, we don’t have the same amount of data or betting activity,” said Jay Croucher, head of trading for PointsBet. “It’s kind of like old-school bookmaking where we put up a number as best as we can make it based on the information available, and we just move aggressively off of sharp money that comes in.

“It’s the Olympics. You’re going to see things that open +500 and are shortened to close at -110. That’s just going to happen. We try to be as ahead of the curve as we can on that kind of stuff.”

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When sports shut down last year, American bettors turned to darts, table tennis and anything else competitive. The bookies will keep the limits moderately low for the obscure sports, while also reigning in the odds.

“The thing to watch with futures wagers is the baked-in vigorish, which is typically quite high,” said Jack Andrews of Unabated.com, a developing website hoping to educate and advocate for bettors. “Bookmakers use vigorish to make up for their uncertainty in the market, and when you’re dealing with Olympic sports, there is often uncertainty. So they will be tough markets to beat.

“The other factor is the bias of [American] bettors towards the U.S. team,” he continued. “[That] may skew the odds as well.”

The time difference also is in play with Tokyo being 13 hours ahead of East Coast time. For instance, the U.S. men’s basketball opener will be Sunday at 8 a.m. Philadelphia time — 5 a.m. for the loonies in Vegas, who will probably just be getting in from the night before.

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“We just had the British Open and that attracted quite a bit of money,” Avello said. “The question is the viewership: How interested are they in this? We’ll see. If they’re really interested, the time difference won’t matter. If they’re saying it doesn’t fit them because they’d rather sleep, it might not do as well.”

Tom Gable, director of the Race & Sportsbook at the Borgata in Atlantic City, smiled at the idea that they’ll be offering swimming for the first time.

“To be honest, I’m not quite sure what to expect. I mean this is the first Olympic Games that we can book since PASPA was repealed,” he said. “It’s going to be interesting to see what people are drawn to, if it’s something that’s going to be appealing to bettors.”