As comic books regained their popularity in the 1960s during the boom of the Silver Age of Comic Books, fans organized comic book conventions, where fans could meet to discuss their favorite comics with each other and eventually with the comics' creators themselves. As of 2006, numerous conventions and festivals are held around the world, with San Diego Comic Con being the largest and best-known convention in the United States.
While some people collect comic books for personal interest in the medium or characters, others prefer to collect for profit. To assist both types of comic book collector, comic book price guides are available and provide estimates of comic book values as well as information on comic book creators and characters. The price guides assign values for comic books based on demand, availability, and the copy's condition. The longest running price guide is the annual Overstreet Price Guide, first published in 1970. Current monthly price guides include Comics Buyer's Guide and Wizard Magazine. The growth of the Internet in the late 1990s saw development of online databases that tracked comic book creators and character appearances and storylines, as well as websites that combine comic book price guides with personalized collection tracking to provide collection values in real-time. The Grand Comic-Book Database is a popular online resource for comic book creator and character information. Popular online price guide and collection tracking services include comicbookrealm.com, comicspriceguide.com, and nostomania.com The increased popularity of online auctioning services like eBay or Heritage Galleries for buying and selling comic books has greatly increased the visibility of actual comic book sale prices, leading to improved price guide accuracy, particularly for online price guides such as nostomania.com that base their values solely on sales data captured from online sources
In response to collectors' interest in preserving their collections, products designed for the protection and storage of comic books became available, including special bags; boxes; and acid-free "backing boards", designed to keep the comic book flat.
Once aware of this niche market, the mainstream press focused on its potential for making money. Features appeared in newspapers, magazines and television shows detailing how rare, high-demand comics such as Action Comics #1 and Incredible Hulk #181 (the first appearances of Superman and Wolverine, respectively) had sold for hundreds or even thousands of dollars.
During this time, comic book publishers began to pander specifically to the collectors' market. Techniques used included variant covers, polybags, and gimmick covers. When a comic was polybagged, the collector had to choose between either reading the comic book or keeping it in pristine condition for potential financial gain, or doing both by buying two copies. Gimmicks included glow-in-the-dark, hologram-enhanced, or foil-embossed covers. Gimmicks were almost entirely cosmetic in nature, and almost never extended to improved content of the comics. However, many speculators would buy multiple copies of these issues, anticipating that demand would allow them to sell them for a substantial profit at some nebulous point in the future.
This period also saw a corresponding expansion in price guide publications, most notably Wizard Magazine, which helped fuel the speculator boom with monthly columns such as the "Wizard Top 10" (highlighting the "hottest" back-issues of the month), "Market Watch" (which not only reported back-issue market trends, but also predicted future price trends), and "Comic Watch" (highlighting key "undervalued" back-issues).
Ironically, the speculators who made a profit or at least broke even on their comic book "investments" did so only by selling to other speculators. In truth, very few of the comics produced in the early 90's have retained their value in the current market; with hundreds of thousands (or, in several prominent cases, over ten million) copies produced of certain issues, the value of these comics has all but disappeared. "Hot" comics like X-Men #1 and Youngblood #1 can today be found selling for under a dollar apiece.
Veteran comic book fans pointed out an important fact about the high value of classic comic books that was largely overlooked by the speculators: original comic books of the Golden Age of Comic Books were genuinely rare. Most of the original comic books had not survived to the present era, having been thrown out in the trash or discarded as worthless children's waste (just like baseball cards typically were at that time) by parents (stories of uncaring parents throwing out their kids' comic book collections are well known to the Baby Boom generation), or recycled along with other periodicals in the paper drives of World War II. As a result, a comic book of interest to fans or collectors from the 1940s through the 1960s, such as an original issue of Superman, Captain America, Challengers of the Unknown, or Vault of Horror, was often extremely difficult to find and thus highly prized by collectors, in a manner similar to coin collectors seeking copies of the 1955 doubled die cent. In many ways, with an enormous supply of high-grade copies, the "hot" comics of the speculator boom were the complete opposite.
The bust can also be linked back to some of the series that caused the boom, a few years earlier. DC's decision to publish two blockbuster stories depicting the loss of their two major superheroes ("Knightfall" — the breaking of the Batman — and "The Death of Superman"), and their subsequent flooding of the press as to its supposed "finality", is considered by some collectors to have started a slow decay within the non-regular buyer comic community which then led to drops in sales. Many comic retailers believe that numerous comic speculators took the death and crippling of two major characters to signify the end of the Batman and Superman series. As many comic readers and retailers knew full well, very little in comics actually changes with any finality. Many aspects of the status quo returned after the story arcs were over (Superman died, but was resurrected, and Batman was crippled, but eventually recovered).
Many comic speculators who were only in the market to see important comics mature, then sell them for a tidy profit, didn't quite understand how quick the turn around would be on the story recant, and many rushed out to scoop up as many copies of whatever issues were to be deemed significant. Comic shops received not only staggering sales during the week that Superman died, but also had to try and meet the demand. This led to the saturation of the market and the devaluing of what was thought to be the end of an American icon. Some comic book retailers and theorists deem DC's practices in the press forum and their relationship with the non-specialized consumer to be grossly negligent of the status of the market, and that their marketing campaign, whereas most likely not malicious in intent, spelled doom for the speculator market and comic sales in general. Others place the blame for the comic market crash on Marvel (whose product line had bloated to hundreds of separate titles by late 1993, including the poorly received "Marvel UK" and "2099" lines) or creator-owned upstart Image Comics (who fed the speculator feeding frenzy more than any other comics publisher).
Other publishing houses had different problems. Valiant Comics — at one point the 3rd largest comic book publisher — was sold to the video game giant Acclaim Entertainment for $65 million in June 1994. Acclaim renamed the line Acclaim Comics in 1996. Their primary motivation was to make the properties more suitable for use in video game development. Eventually, Acclaim filed for bankruptcy following the collapse of its video game business. The miniseries Deathmate — a crossover between Image Comics and Valiant Comics — is often considered to have been the final nail in the speculation market's coffin; although heavily hyped and highly anticipated when initially solicited, the books from the Image Comics side shipped so many months late that reader interest disappeared by the time the series finally materialized, leaving some retailers holding literally hundreds of unsellable copies of the various Deathmate crossovers. Other companies, such as Continuity Comics, Defiant Comics, Triumphant Comics, and Malibu Comics also ceased publication in the period between 1993 and 1997.
In the 2000s, prices for rare near-mint comics rose steadily, doubling in some cases. This was aided in part by newly-established comic book grading companies, such as Professional Grading eXperts LLC (PGX) and Comic Guaranty LLC (CGC). Improved accountability has increased collector confidence, although some collectors have complained that the market has become more about speculation instead of being focused on the art and stories.
PET film, polyethylene or polypropylene storage bags are popular, and allow a comic to be "bagged" in a contained environment, and have become the traditional way of storing comics. Most comic shops now sell comics already in bags, although the quality of the bag can vary. It should be noted that even some plastic bags are not considered "archival safe" because various plastic compositions may contain elements or have other properties that could harm the comic in years to come. Only PET film is truly considered archival safe as polyethylene and polypropylene will eventually break down. It is debatable whether these bags are sufficient to protect comics from the acids of cardboard storage boxes as mentioned above.
Corrugated plastic boxes, preferred by some collectors, offer greater protection against acid while also offering better protection against moisture damage and vermin damage. Original art can also be better protected against direct sunlight as well as acid deterioration by using an archival quality frame coupled with glass which has been treated to protect against ultraviolet rays.
In the column Comic Book Vitamins on the Project Fanboy website, Steven Sykora discussed the controversial but increasingly popular way to preserve collections which entails submitting your comic books to the CGC where comics are inspected for flaws, graded accordingly and placed in an inner well - a sealed sleeve of Barex, a highly gas-impermeable plastic polymer. Then, the comics are sealed through a combination of compression and ultrasonic vibration in a transparent, hard plastic capsule. This process is often referred to in slang as "slabbing" and there is debate as to whether this provides better protection for your comic books than an acid-free backing board and Mylar sleeve.
Comic collectors have undergone as many changes over the years as the medium they love, as westerns and pulp horrors have given way to super–men and mutants, and comics have moved from disposable newsstand monthlies to collectibles from specialized stores and now to trade paperbacks available at major–chain bookstores all over the country. Although sometimes portrayed negatively by popular media (such as the depiction of the character of Comic Book Guy in the TV show The Simpsons), comic book collecting is a wide–spread hobby, and popular venues such as the San Diego Comic-Con attract more than 80,000 fans over a four day period each year.
As comic book characters become more mainstream through adaptations in other media (primarily television and film), much has been made in recent years of celebrities, particularly actors, who are professed comic book collectors, such as: