Analyzing the Hottest Silver Age Comics of the last 30 days is a case study of both what lies behind us and speculation about what lies ahead. Normally this list is populated with books driven by speculation from future MCU or DCEU projects. And while books like Sub-Mariner #1 and Fantastic Four #52, this month's list of biggest risers gets back to comics roots. The most popular books this past month were the old faithful from the Silver Age: Spider-Man, X-Men, and the Avengers. Investors found books that were undervalued in those titles and are jumping on them.

Here are the five highest risers among Silver Age books in the past month.

Amazing Spider-Man #20 (+79)

Among all of the "blue chip" villains introduced in the first 20 issues of the original Amazing Spider-Man run, Scorpion is often overlooked and has seen values for this issue that don't rival Dr. Octopus, Sandman, Green Goblin, or Mysterio, among others. Maybe there has also been some frustration from lack of MCU movement since Mac Gorgan was introduced the Spider-Man: Homecoming, but nothing materialized since.

However, as investors and speculators become smarter on what books to target, a relatively cheaper key villain in the first 20 issues of Spider-Man is a hot target. Just two years ago a CGC 6.0 copy (50th percentile on the census) sold for $587 and $624 on eBay auctions. Imagine getting a book like this in that grade now. It will cost you at least $1,100 to get in at that grade now. And it sold for over $1,400 just months ago.

As we know (and will see on this list), the value of Silver Age Spider-Man is never going to be a bad bet. This is the capstone character in the most vaunted time in comics history. Any grade of this book is a good long-term investment.

Amazing Spider-Man #8 (+61)

Then there is a whole other level of valuable Spider-Man books that make up the 10 first appearances of the character. Including Amazing Fantasy #15 and the first nine issues of the Amazing Spider-Man run, you have some absolute classics. Besides the first appearances of Peter Parker, Aunt May, and J. Jonah Jameson, you have first appearances for Chameleon, Vulture, Doc Ock, Sandman, Lizard, and Electro.

Issue #8 does have a first appearance component; it is the first time we see Living Brain. But compared to those other Hall of Famers, this book has always fallen flat. Living Brain has never made a major dent in Marvel comics lore, which means this book has always been relatively affordable.

Just two and a half years ago, this book in a CGC 8.0 (top 17%) sold for under $1,000. Lately, that grade has sold for over $2,000 and even grade 6.0 have crossed the $1,000 threshold.

Avengers #11 (+57)

I wrote a more extensive piece about this book earlier in the year, so there isn't too much more to add to that. But as a book that features the first time Spider-Man and the Avengers cross paths, this specific issue has always been underrated and undervalued. It also includes the second appearance of Kang the Conqueror. This might have something to do with the spike in value after the D23 announcement and footage that was shown for Ant-Man and the Wasp: Quantamania.

But in the end, the first time Spider-Man and Captain America meet. The two most iconic Marvel characters ever created. It's a wonder it took collectors this long to catch on to this book's significance, but recent sales show that the respect is finally being given.

The 50th percentile for this book on the consensus is about a CGC 7.0. That grade sold for $699 on eBay in August while the same grade sold for just $481 six months earlier. That's a massive increase in a short time frame, and I don't see this book cooling down in any meaningful way soon.

Amazing Spider-Man #23 (+54)

This very early Amazing Spider-Man book likely has been undervalued for some time due to one specific reason. At least according to Key Collector Comics, it is the first Amazing Spider-Man book to not feature either a first or second appearance of a new character or a first major event (such as Amazing Spider-Man #5 or Amazing Spider-Man #16). As the listed third appearance of Green Goblin, this book has carried less historical weight than others before it.

But now this book has been hot for the last 30, perhaps simply because of its age and affordability. There has been a resurgence of Green Goblin-related material since Spider-Man: No Way Home and the recent introduction of Gold Goblin. But deal-seeking early Spidey collectors probably just found this book more accessible than others.

Case in point: a CGC 9.2 of this book sold at auction last month for just $1,500. There are only 25 higher grades in the world. Even a CGC 8.0 copy that sold for$ $460 last December is now going for $640. Despite the huge percentage hike, that's still a very affordable book.

X-Men #12 (+48)

I was surprised to find in the GoCollect database that there are more than 3.000 blue and yellow versions of this available in the census. Add in a couple thousand potential CBCS copies plus the raw copies for sale out there, and this is a book with a lot of supply. Still, it is a book that has 56 recorded sales in GoCollect. Not to mention sales that might have happened at cons, Instagram, Facebook, Whatnot, or other marketplaces.

There was a speculative report last month that the newly announced Captain America: New World Order could usher in an introduction to Juggernaut. In that theory, the New World Order, established in the comics by Red Skull with assistance from Juggernaut, battles the Avengers in order to free Hulk. If any of that is part of the film, Juggernaut could be on the way. But in a more simple, straight line of speculation, we know Charles Xavier is coming soon. Juggernaut (or Cain Marko) is Xavier's brother. Introduce Professor X and you have a path to Juggernaut.

Anything at a 5.0 or above is going to run you at least $1,000 right now. Even CGC 4.0 copies that sold between $640 and $720 in June have now crossed $1,000 for the first time earlier this month.

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*Any perceived investment advice is that of the freelance blogger and does not represent advice on behalf of GoCollect.