CGC Graded 9.9
A CGC grade of 9.9 denotes 'Mint,' which is theoretically as high a grade as a normal comic book could achieve; some collectors have debated the need for a Gem Mint (10.0) grade since CGC's inception.Nevertheless, a 9.9 grade is very strict and is nearly as difficult to achieve.
In previous decades, collectors who purchased comics listed as 'Mint' in dealers' catalogs often didn't know how their books would actually look once they were received; there was no universal standard as to what counted as a Mint book.
Now, with the advent of CGC's grading services, collectors have examples against which they can judge their own grading skills.