July 2018 had 6,933,449 units in the top 300 comics list, an increase of 473,642 units from last month. The increase seems small given the six first issues in the top ten and a massive bump in sales on Batman #50. All of the sales increase on Batman #50 was lost and then some on Batman #51. The spoiling of the story a few days before release factors into that, as well as the direction the story took.
This trends of a sales bump on a given issue followed by the the nearly complete evaporation of that sales bump on the next issue is commonplace. Sometime the issue after keeps a little of the sales increase. Sometimes the next issue sold how the title was trending before the sales bump. In most cases, the sales impact the the key plot point or incentive cover is focused on the particular issue with minimal impact, if any, on later issues. The result is an issue not having a multiple covers is less common than those with variant and incentive covers. In some cases this is basic profiteering. Publishers exist to make money and incentive covers do that. In other cases, the additional covers can help keep a title afloat. That isn't a bad thing either, particularly for the creators and fans of those titles.
Marvel Comics placed 3,131,031 units in the top 300 comics and was up 289,143 units in the top 300 compared to last month and accounted for 45.16% of the total units for the top 300 comics.
DC Comics placed 2,466,932 units in the top 300 comics and was up 153,384 units in the top 300 compared to last month and accounted for 35.58% of the total units for the top 300 comics.
Image Comics placed 615,896 units in the top 300 comics and was down 128,907 units in the top 300 compared to last month and accounted for 8.88% of the total units for the top 300 comics.
The premiere publishers accounted for 96.95% of the units in the top 300 comics this month while all of the other publishers with items in the top 300 accounted for 3.05% of the units.
The up-swing of 2,802,126 units from new and increased sales was enough to compensate for the down-swing of -2,328,484 units from lost sales.