Dr. Giganto

I couldnt really find a record for Vegas's sportsbooks, but there's an important thing to remember. Vegas's goal isnt to set a "fair" line. Their goal is to set a line such that an equal amount of money gets wagered on both sides.

Just in case some of the people reading this don't really know how sports betting work, I'll use the hypothetical example of the Cleveland Indians vs. the New York Yankees in the ALDS.

Let's say Vegas thinks the teams are exactly 100% even, so it sets the line at even money. Vegas takes 10% of all winning bets. This is called the "vig". So now, let's say 10 million gets wagered on the Yankees, but only 5 million gets wagered onthe Indians. If the Yankees hold on to win, Vegas will have to pay out $9 million to the people who bet on the Yankees ($10 million minus the 10% vig), but they only collect $5 million from the people who bet on the Indians. Thus, Vegas loses $4 million from this series. Using the same calculations, Vegas would win $6 million if the Indians win. But still, there is a chance of a big loss.

Now, let's say instead, Vegas sets line at Yankees -150 and Indians +140. That means that every $1.50 wagered on the Yankees will pay out a $1 profit if the Yankees win, and each $1 wagered on the Indians will pay a $1.40 profit if the Indians win. Now, let's say $8.85 million is wagered on the Yankees and $6.15 million is wagered on the Indians.

If the Yankees win, Vegas pays out $5.9 million to the people who bet on the Yankees, but collects $6.15 million from the people who bet on the Indians, giving a profit of $250,000.

If the Indians win, Vegas pays out $8.61 million to the people who bet the Indians, but collects $8.85 million from the people who bet the Yankees, giving a profit of $240,000

By adjusting the line, the Vegas guaranteed themselves a profit, whereas before they had a 50% chance of a huge loss. No matter who wins, Vegas makes a profit of about $250,000

So, it's not in Vegas's best interests to set a "fair" line. Vegas tries to set the line so that the appropriate amount of money will be wagered on both sides to guarantee a profit

The general public is more likely to bet on the Yankees than the Indians, since hte Yankees are a much higher-profile team, so Vegas has to set the line accordingly, even if they believe the Indians are the better team.