Does anyone know why this particular issue is so valuable? I'm assuming it's some mix of investment, timing, sentimental value, and rarity. But which ones particularly?
it’s valuable for the same reason the mona lisa is valuable. it’s iconic, it is a singular object, it is one of a kind, it is a stable investment vehicle. they ain’t making more of them.
I always wonder exactly how difficult it would be to get the paper, ink, staples, etc exactly right. I'm sure it would be difficult but 9m is a big payoff if you can.
Even if you could duplicate it down to the molecule I would assume it wouldn't hold the same value since it doesn't have the same history. Assuming you'd want to sell it in good faith as a replica.
It's also not the first Superman comic, what about Action Comics #1?
Why is the Call of Cthulhu (Weird Tales, Feb 1928) about $50k?
Or in terms of characters, what makes Superman worth 3x more than MARVEL #1 or Batman?
Superman was arguably the first super-hero, and certainly the first successful/popular one. And Superman #1 is the first time a super-hero got their own dedicated comic book. It has long been generally considered the third-most desirable comic book issue in existence, after Action Comics #1 (first appearance of Superman) and Detective Comics #27 (first appearance of Batman).
This copy of Superman #1 was graded as a 9.0, which basically means it's like-new, despite being 86 years old. And it's naturally in that condition without ever undergoing restoration, which affects the value. Of all known unrestored copies of Superman #1, this copy is in the best condition.
That said, there are at least three known comic book copies that would be valued more highly: two known unrestored 9.0 copies of Action Comics #1, and one known unrestored 9.2 copy of Detective Comics #27. If any of those were to be sold at auction today, their value would almost certainly be a lot higher than $9 million, in part due to this Superman #1 auction setting a recent precedent.