Gem rate, and why it moves prices

The definition

Gem rate is the number of copies at the top standard grade divided by the total the grader has graded, expressed as a percentage. For PSA that is PSA 10s over total graded; Assetra reports it per grader, so a card can have a PSA gem rate and a CGC gem rate. If PSA has graded 5,433 copies of a card and 123 are PSA 10, the gem rate is 2.3 percent.

What is high and what is low

Print quality decides most of it. Some modern sets gem on a majority of submissions, because the cards leave the factory well centred and clean. Vintage holographic cards from the 1990s, with their soft corners and print lines, can gem at a few percent or less. Japanese printings generally gem at higher rates than their English counterparts.

Submission behaviour matters too. Collectors pre-screen expensive cards and only send likely 10s, which pushes the gem rate up; cheap cards are sent in bulk, which pushes it down. A gem rate is a fact about what was submitted, not about every copy ever printed.

Why it moves prices

The gem rate sets the relative scarcity of a 10 against a 9. When nine in ten submissions gem, a PSA 10 is the ordinary outcome and sells close to the PSA 9. When one in forty gems, the 10 is the prize and the gap can run to many multiples. Read the gem rate together with the absolute population: a 2 percent gem rate on a card with 50,000 graded copies still leaves 1,000 PSA 10s.

Assetra states the gem rate in the card’s market overview and in the population section when the data supports it, next to the latest PSA 9 and PSA 10 sales. Browse by set from the price hubs.