What is line movement? Why you need to pay attention.

What is line movement?

In sports betting, line movement is the idea of a betting line moving from the time the opening line is released to the start of the game. It could also be live line movement that occurs during the game, but for this article, we will just be discussing the changes in betting lines prior to the game beginning.

Being able to properly predict line movement and the reason as to why the line moves can give gamblers a huge advantage against the sportsbooks. This will help you get the best price for the bets you are wanting to place as well as identify opportunities for “middling” bets and hitting lines at key numbers.

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What are betting lines?

Prior to understanding the idea of line movement, it is best to begin by fully understanding betting lines in general. A betting line could be a number of different things such as a moneyline, over/under, prop bets, point spread, etc. All of these have the potential for movement prior to the game starting and all could equally offer advantages for sharp bettors.

A betting line is what the sportsbooks place the odds at for any given type of wager prior to the start of the event. Let’s look below at the options that a sportsbook may offer prior to an NFL game beginning:

The betting line set for the spread prior to this game beginning is the Packers as 1.5-point favorites, which means they would need to win this game by at least 2 points in order to cash a bet towards them. The -110 would require a $110 bet in order to profit $100 off this wager. If just betting the Packers to win outright on the moneyline, the gambler would need to place $130 in order to win the same $100 profit.

Why line movement may occur

Continuing with the example of the NFL, sportsbooks will try to get their odds out as early as possible. Throughout the season, this will typically occur on Monday for the upcoming Sunday’s set of games. If you follow the NFL closely, you know how much news can occur throughout the week. This is where tracking line movement can be a big edge in gambling.

Lines change due to injuries

Let’s say for the above example that Aaron Rodgers had left the previous week’s game with a hand injury and starts the current week listed as questionable. The Packers are a far different team without their star quarterback. If he gets ruled out late in the week, the odds may then look like this

There are a number of reasons why line movement may occur but injuries to key players is one of the main causes. Later on we’ll get into when to place bets and how to use tracking injuries to your advantage.

Line moving due to amount of bets placed

Sportsbooks will always try to maintain a competitive advantage over the gambler. They set lines at certain numbers that they feel are the best combination of being fair while still giving them the edge. As bets are placed and money comes in, these lines will adjust in order for them to maintain that advantage. Checking out some odds for an NBA game will show just how this works for the sportsbooks when it comes to spread bets.

• Los Angeles Lakers +4.5
• Dallas Mavericks -4.5

Now let’s say for this example that the public hammers the Mavericks and the sportsbooks take on a large amount of money towards that side. Smart sportsbooks will want to collect money in the favor of the Lakers as well to balance out their risk so they will oftentimes adjust the line to make the Lakers appear more enticing.

• Los Angeles Lakers +6.5
• Dallas Mavericks -6.5

In theory, this will cause bettors to begin targeting the Lakers and even out the risk for the oddsmakers. While this sort of movement is done for the sportsbooks to maintain an edge, there is a big advantage to be had for sharp bettors as well, which we will get into a little later on.

Line movement will generally occur due to one of three reasons: injuries, money coming in, or other news stories released prior to the game starting. Deciding when to place your bets to counteract the movement is what can take a beginning gambler and turn them sharp in a hurry.

How to use line movement to gain an edge

There are two main ways to use line movement to gain an edge in sports betting and ensure that you are placing the best bets. First would be if you already know which side you want to bet. The other is if you want to track and bet based on value in odds.

Favorites vs underdogs

One of the basic betting strategies to follow is to bet the favorites early and bet the underdogs late. The favorites on a moneyline or point spread tend to be the more popular side for the public to bet. As we learned above, the more money that sports bettors place on one side, the more the line will shift in favor of the other. If the public tends to place money on the favorites, you will get worse odds on them as we near the start of the game. Remembering that a lot of casual bettors don’t even consider odds when placing wagers allows us to take advantage of this pattern.

The counter argument works as well. An underdog will typically get better odds as you near the start of the game. In terms of America's most popular sport, the NFL, this means tracking the line as the week progresses. On Monday, moneyline odds may look something like this:

• Tennessee Titans: +130
• Indianapolis Colts: -120

By our rule above, the public will begin targeting the Colts and we will wait in order to place our bets on the Titans. By Thursday, it is very likely for the odds to look more like this:

• Tennessee Titans: +145
• Indianapolis Colts: -135

A $100 wager on the Titans moneyline will profit you an extra almost 15% just by being patient.

This method is most effective if you know what side of the matchup you are wanting to bet prior to the odds getting released. Set a number in your head that you are comfortable betting and based on where the sportsbooks release the odds, you will know whether to wait for the right odds or bet it early on. Remember that if the number never reaches your desired odds, a bet doesn’t always have to be placed.

Sep 11, 2022; Houston, Texas, USA; Indianapolis Colts wide receiver Michael Pittman Jr. (11) runs with the. Ball as Houston Texans cornerback Steven Nelson (21) defends during the game at NRG Stadium. Mandatory Credit: Troy Taormina-USA TODAY Sports

Line movement determining which side to bet

If you are not certain which side you are wanting to take once odds are released, you can track line movement leading up to the start of the game to make this decision for you. Identifying value will help you gain the most edge when handicapping sports. Do this by closely monitoring the line movement. Let’s consider this NFL point spread being released on a Monday morning:

• New York Jets: +7.5
• New England Patriots: -7.5

If sharp bettors and the public alike believe the Patriots will win by more than just one touchdown, the week can begin by a certain sportsbook taking on a lot of money towards New England. Odds at this specific site will shift in this direction:

• New York Jets: +9.5
• New England Patriots: -9.5

A two-point movement in odds is considered a very big adjustment in the NFL. Now comes the advantage we as handicappers can find. Just because one site shifted these odds, doesn’t mean that all sportsbooks did. Maybe the money put in at one location doesn’t match another, so the other sportsbooks haven’t adjusted yet. By tracking line movement throughout the industry, it may provide an opportunity for gamblers to still capture the odds of New England -7.5 somewhere else, thus providing great value leading up to kick off. To see more detail on shopping for lines, check on the article here.

Sharp vs public betting

In sports betting, a sharp is considered someone who bets heavily and potentially does it professionally based on their volume. The public is more the casual bettor looking to place bets for fun to have some action in play while watching sports. Tracking the difference between these two types of handicappers gives us an advantage when placing our own bets.

The “sharp money” is the side of the odds that the majority of the sharps are on, and this is considered the side of the bet that is most likely to hit. Tracking sharps is typically a way to gauge where the smart bettors are investing. You can often find the sharps placing bets prior to the lines moving, which then gives us an opportunity to take advantage.

The real information to be tracking when looking at the sharps vs the public is to find the difference between total money placed vs total bets placed. Sharps will be placing bets at much higher dollar amounts than the general public. Because of this, the number of bets placed does not always line up with the amount of money placed. If one side of the bet has received 60% of the money but only 40% of the total bets, you can assume that’s where the sharp money is at. Let’s take a look at the MLB odds and percentages below:

This matchup between the Dodgers and Cubs is a great example of tracking sharps vs public betting. By looking at the numbers above, we can see that the public is heavy on the Dodgers but the % of money in play does not line up with the total number of bets. The sharps may be leaning towards the Cubs in this game which, as the day progresses, could lead to some line movement.

It’s also worth noting that this lines up with one of our original points that the public tends to lean towards the favorite, as you can see with the above early day MLB odds.

You can use a site such as Action Network to track % of bets vs % of money.

Reverse Line movement 

As mentioned prior, sportsbooks will set a line and if they receive a heavy amount of bets on one side, they will move the line in favor of the other with hopes of receiving bets closer to 50% on each side, locking in their profit. However, the line will sometimes move in the opposite direction and away from the popular side. That’s what is referred to as reverse line movement.

A simple example in the NFL would be the Giants opening at -4.5 and moving to -3.5 despite receiving 75% of the bets. Or in a moneyline situation like the NHL, the Bruins moving from -130 to -115 despite receiving over 60% of the bets placed.

What causes reverse line movement?

Since we already discussed that sportsbooks move lines based on bets coming in, it should always stand out to us when we properly identify reverse line movement. In the above section about sharps vs the public, we discussed how to track where the sharps are placing their money. This is what will often cause reverse line movement. The sportsbooks also assume that the sharps handicap games better than the public and will adjust lines according to their wagers as opposed to percentage of bets placed overall. Just like how we try to track total bets placed vs total dollars placed, the sportsbooks do the same, and lines change accordingly.

September 18, 2022; Santa Clara, California, USA; San Francisco 49ers wide receiver Deebo Samuel (19) is tackled by Seattle Seahawks safety Josh Jones (13) and linebacker Jordyn Brooks (56) during the second quarter at Levi's Stadium. Mandatory Credit: Kyle Terada-USA TODAY Sports

How to react to reverse line movement

While it is a very important concept to track and follow, it is, however, difficult to take advantage of reverse line movement. We can assume that once the lines change, there is no longer the perceived value that there was before. This circles back to the importance of having more than one sportsbook that you use. By identifying reverse line movement at one location, if timed correctly, you can find value at another. Like mentioned prior, just because one sportsbook has adjusted odds, doesn’t mean that they all have.

For example, if the Rams opened at -3.5 and very quickly jumped to -5.5 but using one of the tracking tools discussed prior, you can find that only 40% of the money has been placed on them, this is a signal of reverse line movement. We should assume that the sharp money at one book perceives the -3.5 spread as value. In this example, quickly shop around to see if there are any other places still offering the -3.5 and place your bets there.

Common terms to know

There are a few common terms and strategies that experienced bettors use when it comes to line movement. We will focus on three important ones - middling, key numbers, and buying points.

Middling

By definition, “middling” refers to betting both sides of a bet after a line has moved leaving the potential for a “middle” outcome when the result would end with both bets being winners. While this is a potentially risky strategy, if done correctly, it can result in doubling your winnings. Let’s look at this college football example below.

Opening odds:

• Texas +7.5
• Miami -7.5

Let’s assume that a bettor takes Texas at +7.5 with hopes that they will keep the final score within 7 points. Even if Miami wins, a bet placed on Texas at +7.5 is still a winner with a final score of 27-20.

Now after the majority of sharp action comes in on Texas, the odds may swing in favor of Miami:

Odds after line movement:

• Texas +4.5
• Miami -4.5

With these adjusted odds, Miami now only has to win by 5 points in order to cash a bet on them. The final score of 27-20 would now cash a bet placed on Miami as opposed to originally favoring Texas.

If a handicapper placed an original bet on Texas at +7.5 then was able to get Miami at -4.5 later in the week, the final score of 27-20 would ultimately cash both bets. This would be an example of “middling.”

Key numbers

The best example of how to utilize key numbers takes place in football. This is mostly due to other sports scoring in increments of one but the NFL and College Football has points scored in 3s and 7s. This takes on a whole new strategy when it comes to looking at point spreads, which is the most common type of betting for the NFL.

Watching for key numbers allows gamblers to put together specific strategies when tracking line movement. Finding spreads that are just over or under 3 or 7 fit into this example. Personally, I specifically track key numbers when betting the underdog side of point spreads.

• Baltimore Ravens -3.5
• Cleveland Browns +3.5

This is an example of a spread with key numbers associated. According to NFL historical scoring, just over 14% of all games have ended in a result with a 3-point difference. When looking at the above odds, if you believe it may be a somewhat close game, odds say that it could very well end in a result of something like Ravens 27 vs Browns 24. This 3-point difference would end up a winning bet for the underdog on the point spread.

If odds for a game open with the underdog at +2.5, it may be worthwhile to wait as the week progresses to see if you can find some betting line moves in the favor of the underdog and the spread may ultimately cross that key number of three.

Buying points

The third strategy is the process of paying extra juice to the sportsbook in order to get a spread that you want. Most sports betting sites will allow you to buy points in the direction of the favorite or the underdog. Taking into account the theory of key numbers that was discussed above, it may be worth taking odds of -120 instead of -110 if it means getting a number on a specific side of 3 or 7.

Most sportsbooks will charge the bettor ten cents of juice in order to move the line half a point. If odds open with the favorite at -5.5 but you would prefer to get them at -4.5 instead, most likely you will need to place that bet with a payout of -130 as opposed to the original line of -110.

Accurately predicting line movement can help guide you to when you should or shouldn’t buy points. If a spread opens at -6.5 and you think it will move towards a number of -7.5, buying in the opposite direction gives you much better odds of hitting your bet for less than you would pay at the start of the game.

Line movement in specific sports

The basic idea of line movement remains the same across the sports betting industry, but the nuances and strategies can change sport to sport.

NFL

As mentioned prior, key numbers are more important and influential in the NFL than any other sport. Finding those key numbers or buying points to get to them is a great way to get in front of line movement happening.

Sometimes, sportsbooks won’t move their lines off of the key numbers. Instead they will adjust the amount of juice needed for getting the spread. For example:

• Packers -3 (-110) bet $110 to win $100
• Vikings +3 (-110)

Even if there is a large amount of money that comes in on the Packers, sportsbooks may still be hesitant to come off the -3 number. Instead, they may adjust the odds to the following:

• Packers -3 (-120) bet $120 to win $100
• Vikings +3 (+100)

NBA

Key numbers are not as important when it comes to the NBA but there is still plenty of line movement throughout the day. The most important factor in the NBA are the injuries that pop up. A single NBA team may have around five players all listed questionable when the lines open in the morning. Tracking news throughout the day is crucial for finding value in the NBA.

If LeBron James is questionable to start the day and the Lakers open as a -4.5 point favorites, the second he gets ruled out, they may even end up as underdogs. Following along with news closer than the sportsbook is a way to capture great value.

MLB

The run line is the most popular form of betting for baseball. The run line is a combination of a spread and a moneyline. See below:

• Dodgers -1.5 (-125)
• Giants +1.5 (+110)

In this example, the Dodgers would need to win by at least two runs to cash their run line bet with a payout of -125 (bet $125 to win $100).

With betting the run line, it is important to know that the spread never changes from 1.5 so the only line movement that we will find will be the juice associated with that spread.