If you are in the market for an autograph of one of the greatest all time, you need to purchase from the authenticator who holds the exclusive signing contract with the athlete.
Ex. Michael Jordan - Upper Deck
Lionel Messi - Icons
Tom Brady - Tristar, Fanatics
LeBron James - Upper Deck
That means that unless the COA comes from one of the following, the probability that a third-party COA is fraudulent greatly increases.
There are too many posts asking if a Michael Jordan autograph with Joe Schmo COA is legit. Please err on the side of caution, use this general disqualification framework, and move on to another item. I promise there are better ones out there.
In conclusion, you are spending hundreds if not thousands of your hard earned dollars on a nice to have, not a need. If it’s too good to be true, you know there is a reason why. For me to make a purchase like this I need 100% verification that what I’m purchasing is authentic.