London High

The MLB data covers 16 seasons (including the current one), which is 38,171 games, and never has there been a Total higher than 14.5 runs.

Until today. 

Unless there's an adjustment, the London Series game between the 'home' Boston Red Sox and visiting New York Yankees had the Total set at 15, not high enough to prevent Overs from another comfortable win.

The previous high of 14.5 runs was set in April 2010, for a day game at Wrigley Field, and again the outcome was Overs as the Chicago Cubs beat the Arizona Diamondbacks 13-5.   

Since 2007, there have only been 12 matches with a Total higher than 12.5, and 9 have gone Over. Those public biases helping the informed bettor perhaps, although it's a small sample.

Incidentally, today is the first time ever that two such games have been played on the same day.

The higher totals tend to be set in National League ballparks of course, and all-time the record in these games (Total 13+) is 36-27-7, which at Pinnacle's -105 works out to an ROI of 10.4%.  

In matches where the two teams scored 13 or more between them in the previous game, the ROI is 26.2% suggesting that when the batters are hot, they stay hot.