This book is bucking a general trend for DC Comics back issues.
The comic book market is more and more becoming driven by key issues. While some collectors are still putting runs of titles together, others choose to pick only the most important books from different series.
Silver Age Batman issues are strong sellers, but that is the exception for DC Comics superheroes, which have been less popular for a while -- mostly due to DC's sluggish production of comic book movies.
The deep pink cover of Batman #171 makes it very hard to find a copy above FN (6.0). The slightest crease will break color on the front.
It's hard to recommend this book lower than CGC 7.0 for that reason. There are simply too many average copies around. When you want to sell an investment comic, typically it helps if you are not competing with too many similar issues.
If you can afford it, higher than 7.0 is a good place to put money, but IF is a big word currently! This book has jumped a lot in the last couple of years:
You can see where the price compression begins. The big jump is from 6.5 to 7.0. Below that, a couple of hundred bucks separates all the other grades.
That tells me there are too many copies of mid-grade books available.
This book has posted 20 percent gains in the past 18 months. Not spectacular, but Riddler is long overdue a movie comeback.
Have this book? Click to appraise its value NOW!