“It’s all what the public believes,” he said.
He faulted grading companies like Professional Sports Authenticator, which is part of Collectors Universe, a publicly traded company in Santa Ana, Calif., that offers authentication services for sports memorabilia and trading cards.
P.S.A. charges up to $5,000 to grade a card. Mr. Moser said that its graders were not as knowledgeable as they purported to be and that they were overwhelmed by the volume of submissions and rushed the process. The grade you get, he said, depends as much on the grader as on the card.
Fraud in collectibles markets is rife but difficult to prove, said Carter Reich, a lawyer who specializes in art fraud cases. He, too, blamed grading companies for not following a universal standard.
“It’s their own standard,” he said, “and some other grading company has a different one.”
Joe Orlando, chief executive of Collectors Universe, referred a request for an interview to his assistant, who provided a statement from P.S.A. that said that it had been fighting consumer fraud for 30 years and that each year it rejected thousands of cards out of the two million it graded.
“Our job is to be skeptical,” Mr. Orlando said in an interview with me last year.
But that does not mean the company always gets it right. The first card that P.S.A. ever graded was a 1909 T206 Honus Wagner. It awarded a near-perfect grade of 8 in 1991.
Mr. Kendrick paid $2.8 million for the card in a private sale in 2007. Despite being the first and highest graded Wagner card, it was dogged by suspicion that its edges had been trimmed.
In 2013, Bill Mastro, who in the 1980s was the king of card sales, admitted to trimming the corners of the card, pleaded guilty to fraud charges and was sentenced to federal prison.