Take note all you DC fans out there. Over the last few months, what many comic book shop owners and industry insiders thought to be an erroneous blip is turning into a trend. DC comics has slowly but surely gained marketshare points to close the gap between its chief rival. Marvel enjoyed a 16 pt lead on DC in May but then saw the gap shrink to 11 pts in June and now 9 pts in July. Many are predicting that with the DCnU debuting this September, DC has a real shot a surpassing the house that Lee and Kirby built.
It should be noted that DC's gains were not at the expense of Marvel but at the rest of the market. With DC's gain, publishers like IDW, Image, and Dark Horse saw their numbers drop. While Amazing Spider-Man #666 [which you can see a preview of here] sat at the top of the charts, selling over an estimated 150,000 units, Captain America #1 came in at a surprising second place, defeating the likes of Fear Itself and Flashpoint.
Be sure to head over to Bleeding Cool as they have a lot more statistical charts for your viewing pleasures.