Everyone knows a PSA 9 is worth less than a PSA 10. Almost nobody can tell you how much less, or that the answer depends almost entirely on when the card was printed. We took every card in our graded database with verified sold medians in both grades, 78 pairs after excluding thin-sample inversions, and computed the 9-to-10 price ratio for each. The curve that falls out is one of the cleanest structural patterns in our data.
Median PSA 9 price as a share of the PSA 10, by era
Why the cliff is a gem-rate story
The discount curve is the gem-rate curve wearing a price tag. A modern card gems so often that a 9 is merely the second-best common outcome, so it keeps most of the 10's value. A 2003 card that gems once in twenty tries makes the 10 a lottery jackpot and the 9 the consolation prize, and the market prices the gap accordingly. Salamence ex from Power Keepers: $4,200 in a 10, $455 in a 9. Sabrina's Gengar from Gym Challenge: $3,591 against $413. The 9 is not a slightly worse 10 in these eras. It is a different asset.
The steepest cliffs on the board
| Card | PSA 10 | PSA 9 | 9 as % of 10 |
|---|---|---|---|
| Zapdos, Generations | $2,800 (3 sales) | $150 (14 sales) | 5.4% |
| Paradise Resort, SVP Promos | $493 (17) | $36 (27) | 7.3% |
| Riolu, Scarlet & Violet | $350 (35) | $35 (86) | 10.1% |
| Maushold, Paldea Evolved | $700 (61) | $76 (124) | 10.8% |
| Salamence ex, Power Keepers | $4,200 (10) | $455 (26) | 10.8% |
| Charizard, SM Black Star Promos | $6,350 (4) | $720 (3) | 11.3% |
| Sabrina's Gengar, Gym Challenge | $3,591 (6) | $413 (26) | 11.5% |
| Arcanine ex, Legend Maker | $6,888 (4) | $839 (17) | 12.2% |
Notice Riolu and Maushold in that list: modern cards behaving like vintage. Both are grading-difficulty freaks, illustration-rare printings with notoriously bad centering, and their gem rates sit far below their era's norm. The curve is not really about age. It is about how hard the 10 is, and age just happens to be the best proxy for it.
Which side is mispriced
A 49% ratio on Umbreon VMAX (PSA 10 $4,300, PSA 9 $2,113, on 354 and 148 sales, the deepest tape in our database) means the market treats its 9s as near-equivalent assets. They are not scarce: the 9 population grows every week. Meanwhile an EX-era 9 at 11 to 17 cents carries the same artwork, era scarcity, and a registry that has essentially stopped growing. If you believe in the card but not in paying the gem lottery premium, the vintage 9 is where that view is cheapest to hold. The modern 9 at half the 10's price is the version of that trade we cannot justify from the data.
All 84 cards in Moonstone's graded database holding a current verified sold median in both PSA 10 and PSA 9 with at least three sales per grade, as of August 26, 2026. Six pairs where the 9 median exceeded the 10 were excluded as thin-sample inversions and disclosed above. Medians come from eBay sold listings individually verified by our pipeline. Era assignment follows set release windows. Sample counts shown per row. Not financial advice.