Nothing on the MLB player props board is currently quoted on both sides at enough venues to measure a vig or a spread. Two-sided prices repopulate as each slate's boards open.
Vig by book — FAQ
What is the vig on a sportsbook prop?
The vig is how much a sportsbook's two prices sum to above 100% once both are converted to implied probability. A -110 / -110 prop implies 52.38% on each side and 104.76% together, so the vig on it is 4.76%.
Which venue has the lowest vig right now?
BeatVig measures this from the live board, so the answer changes with the slate. No sportsbook currently has enough two-sided prices up for the figure to be worth stating.
Do prediction markets charge less vig than sportsbooks?
The comparison is not direct. A sportsbook's margin is inside the price, so the excess over 100% is the whole cost. A prediction market's excess is the bid/ask spread of an order book and its fee is charged separately on top, so comparing implied probabilities alone flatters the exchange.
How is the vig on this page calculated?
Both sides of every prop a venue is quoting are converted to implied probability and summed; the amount over 100% is that prop's vig (called the spread when the venue is a prediction market rather than a sportsbook — see the FAQ above on why the two are not the same cost). The figure published per venue is the median across every such prop on the live board, and the number of props behind it is published next to it.
Why is a venue missing from the table?
A venue appears only once it is quoting both sides of at least 30 props on the current board. Below that a single quote moves the figure by more than three points, so the sample is named rather than rounded into a number.