MyTopSportsbooks Line moves Guide

Understanding what line moves are is essential to building a successful and consistent online sports betting strategy. For those that don’t know what the term represents, we’ll provide insight and examples to ensure you’re well-informed by the time you finish this page.

In our never-ending race to get one over on the bookies and make a profit from sports betting, we often forget an important piece of the puzzle. Bookmakers are in the business of making a profit from their members. Understanding how they achieve that can help you steer clear of the many pitfalls and traps used.

No matter which sport, competition, or team you are wagering on, you must remember the bookies always win. Regardless of the outcome, the odds are set to ensure the house makes a profit. How much of a profit depends on the result, but it’s worth keeping in mind that the top sportsbooks are almost untouchable.

The “juice” or the “vig”  is how sportsbooks create a model where they remain profitable over the long run. Remember, the “vig” is the premium 5-10% you pay to bet on sports.

To remain profitable and appealing to new players, sportsbooks want to encourage equal betting action on both sides of a wager. When betting action is imbalanced, sportsbooks engage in line movement to encourage or discourage bettors from placing wagers on different sides.

This guide from the experts here at MyTopSportsbooks explains the ins and outs of line movements. We talk about reverse line movement, how often bookies’ betting odds are correct, how Vegas sports betting plays a part in your wager, and more. You’ll find it covered in our Vegas betting online article if it’s worth knowing. There’s even info on how to bet both sides and win.


MyTopSportsbooks Line moves Guide

How do sportsbooks set betting lines?

There are many ways to bet on the most popular sports fixtures, including the over or under lines, totals, handicaps, moneyline, prop bets, parlays and more. In the biggest matches played, you’ll notice an ever-increasing number of pre-match and in-play betting odds. These include events such as:

  • NFL Super Bowl
  • MLB World Series
  • NHL Stanley Cup
  • MLS Finals
  • NBA Finals

The Vegas market will set the odds, and then you must follow the lines movement to secure your share of the value. That may be acting early or leaving it late. Knowing when to bet is as important as knowing what to bet on.

What does it mean when a betting line moves? How do you use a reverse line movement tracker? We’re getting ahead of ourselves here, but we’ll cover reverse line movement in sports betting shortly.

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Vegas lines

When the sportsbooks open their lines to bettors, the bookmakers setting the Vegas lines decide based on many factors. First and foremost, they use closely guarded systems (both quantitative and qualitative) to set the odds and price.

While any oddsmaker worth his salt will never reveal their methods, you can count on bookmakers chiefly keeping a close eye on each team’s history, injuries, recent records, and respective home and away records, along with many other more minute considerations.

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After determining what odds they believe will encourage equitable actions on both sides of the wager, sportsbooks and their traders open the sports betting lines for bets. From here, the market unveils itself to the laws of supply and demand. But there’s more.

Unfair odds

Bookmakers strive to create odds that will facilitate action on both sides, but the reality is that this doesn’t often happen. Where bettors are placing the money (the pressures of supply and demand) will create external pressure on bookmakers to continuously tweak their lines as the betting market reacts and responds. This is often seen in the Vegas points totals for NFL.

Lines move in all kinds of betting markets, from simple markets like single bets to more exotic other betting markets. That explains why betting lines move and why you should keep track of the changes.

It is important to remember that sportsbooks strive for not fair odds but attracting equal action on both sides. This can result in intentional mispricing in lines. Of course, this leads to a tremendous value for you, the bettor, and you must act before it’s gone.

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Back any many over-priced selections as possible, and you’ll make a long-term profit. That much is guaranteed and achieved by following the betting line movement for several bets.

Betting line set up for a sportsbook

Let’s now look at how to bet on NFL games in Vegas. To illustrate our example of an ideal distribution for a sportsbook, let’s look at this sample line from Bovada.

Let’s say, hypothetically, by the time the Vegas lines close; bettors are placing units of $110,000 to win $100,000 on San Antonio at +5.5. Similarly, bettors placed $110,000 to earn $100,000 on Denver at -5.5.

No matter what happens in this scenario, the sportsbook is guaranteed to make a $10,000 profit. It doesn’t matter whether this spread was representative of a 50/50 probability. What matters for the sportsbook is that they’re pocketing $10,000. Do betting odds change? Yes. Does it stop the bookies from making a profit? No. So it shouldn’t put you off doing the same.

With this in mind, let’s explore why the betting action might be unevenly distributed and what drives sportsbooks to adjust their betting lines. Things don’t always end up neat for sportsbooks. Learn more about sportsbooksfundamentals with our excellent betting basics guide.

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1. Supply and demand influences line movement

Let’s take the same example above in a different context to illustrate a scenario where a sportsbook would have to tweak its lines.

The game above is set for Tuesday at 10:30 PM, and on Monday and 11 AM, bettors wagered $220,000 to win $200,000 on San Antonio at +5.5. Conversely, bettors wagered $165,000 to win $150,000 on Denver at -5.5.

If San Antonio wins outright or loses by only 5, covering the spread, the sportsbook would lose $35,000. They would have to pay out the $200,000 owed to bettors after San Antonio covered while only receiving $165,000 from bettors thinking Denver could cover the 5.5-point spread.

This is not ideal for a sportsbook, as they always want to profit. That forces the traders to act swiftly to plug the leaks.

Moving the Spread / Total

In the lead-up to the game, sportsbooks would likely tweak the sports betting lines to encourage more action in Denver and less in San Antonio. You might see the odds reformulated as +4.5 for San Antonio and -4.5 for Denver.

If the action was still unevenly distributed, it might be further brought closer to reading +3.5 for San Antonio and -3.5 for Denver. The same logic is applied to making adjustments to the total.

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Adjusting the Odds

It’s also possible that sportsbooks could adjust the odds. For example, to encourage the action on Denver, they could change the payout from -110 to even money and change the San Antonio odds from -110 to -120. This price redistribution would have a similar effect to altering the spread numbers.

Sportsbooks employ the basic economic principles of supply and demand. If the supply (betting volume) isn’t great enough for the result desired, sportsbooks artificially increase the demand by making the price of the line or line itself, on the other side, more attractive.

With an increase in demand comes greater quantity. If the supply (betting volume) is more than a sportsbook wants, they make it less desirable, artificially reducing the demand. With a decrease in demand comes a diminished number of bettors taking the line.

It’s important to remember that vegas lines move in both ways regarding points being offered and the available payout.

2. Injuries, Scratches, Coaching Decisions (External Effects)

Not every change in a betting line is due to the distribution of betting action.

The following are common events that will cause line movements. Weather, major injuries to key players, players who are late scratches, such as being pulled after the warm-up, pitchers, goalies, or any other players who are usually in key positions but will not start the game. Their absence changes the odds.

Weather always plays a role in the outcome of a game. For example, if an NFL game is set to be played outside, and snow is in the forecast, the game will likely have fewer points scored. Many bookmakers will reduce the number of points offered on the over/under bets for that specific game.

If a key player for a team playing is injured (think the Patriots, without Tom Brady), sportsbooks will re-calibrate their odds or line to reflect this information. If the Patriots were heavily favoured in light of this new information, they might become the underdogs.

Reverse line movement explained.

Watch the line-up

Sometimes coaches decide to withhold their top players to mitigate the risk of injury. This often occurs late in the season in the NFL, NBA, MLB, and NHL as teams prepare for their playoff runs.

If this information is leaked, it will drastically alter the odds or line bookmakers place on the event. For example, if the Cleveland Cavaliers aren’t going to dress LeBron, they will definitely not be the odds-on favorites.

Occasionally, a coach will also decide to switch out their starting goaltender (NHL) or starting pitcher (MLB). This will drastically alter the odds or line placed on a game minutes before the action begins.

If the Montreal Canadiens decided at the last minute the give Carey Price a night of rest and play Antti Niemi, this would doubtless impact the line or odds sportsbooks assigned to that game. Making last-minute changes can affect bettorsmultiple bet tickets, so always keep up-to-date with what’s happening before the game gets underway.

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3. Sportsbooks Follow “Sharp” Action

Online sportsbooks are all privy to all of their bettor’s betting history. As such, they know which accounts likely belong to sharp bettors or professional bettors. Usually, the sharps have a higher volume of bets and a sizeable bankroll to back their accounts up. They aren’t too hard to spot.

Knowing where the majority of “smart” money is going on a certain game has influenced sportsbooks betting lines. Sportsbooks engage in line movement to discourage more bets on the same side as the “sharps,” who often exhibit a higher-than-average winning percentage.

This could be the bookies moving their odds in the opposite direction of their opening line to guard against their best sports bettors. You may even see a case where the odds available to the sharps differ from the public betting odds.

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NFL “Middling Numbers”

In football, there are key numbers that bookmakers keep in mind when they are setting the spread and totals.

The scoring structure in football means that most teams win by either 3, 7, 9, or 10 points. Roughly 15% of the time, football games are won by 3 points. 8% of the time, teams win by 7 points. This contrasts with the fact that only about 3% of games end with a 5-point margin of victory.

Oddsmakers are privy to this information and make every effort not to move a line by too much. Bookmakers will go to great lengths to avoid moving a line over a key number whenever possible. If they do, they expose themselves to massive risk. This is because bettors may “middle” them, betting on the spread before and after it moves.

For example, read about line shopping article sportsbooks refer to this massive loss, where bettors win both bets, as getting “middled.” It’s an utter disaster for any bookmaker. It may happen in an NCAAF college football game or a match involving a popular side, such as the Ravens.

Bookies have options

Consequently, when it comes to football point spreads, bookmakers will often instead change the odds of the betting point favorite (instead of the Vegas line) as much as they can before they have to move the spread. However, this isn’t set in stone. So, keep your eyes out for an opportunity to bet the “middle.” It pays off huge in the majority of bets.

If, throughout this article, there have been any terms you are unfamiliar with or want to improve your betting vocabulary, take a look at our complete glossary of sports betting terms for all you need!

Check out other sections of this site for information on free bets, spread bets, more sharp action, how to find the best bets, and where the smart money is this weekend.

Frank Lorenzo
Frank Lorenzo
MTS Co-Founder
Geoff Johnson
Geoff Johnson
MTS Co-Founder