Marvel vs. Capcom 2 managed to sell 1.4 million units digitally almost 10 years after the game's original release
One particularly impressive entry on the list is Marvel vs. Capcom 2, because the listing is actually not all versions of the game, but solely focused on the digital release of the game for PS3 and Xbox 360 back in 2009, which was 9 years after the game had originally been released in arcades and on the Sega Dreamcast.
Click images for larger versions
Even beyond that, it's notable that in-company sales data like this generally tracks shipped numbers, which don't always equate to consumer-sold numbers, but since this was a digital release there's no shipping involved, which means that 1.4 million people purchased the game.
Clearly, there's strong selling power with the Marvel vs. Capcom franchise, as Marvel vs. Capcom 3 also appears on their list with strong sales, with the vanilla version shipping 2.2 million copies and the Ultimate game shipping 1.2 million units.
Obviously, sales aren't an obstacle for a future Marvel vs. Capcom game, so let's hope that Marvel sees the light and decides to shake hands with Capcom again for a future collaboration.
Source: Capcom's Financial Page.