SWSH07: Evolving Skies Boost Shake 229/203: PSA 9 vs PSA 10
SWSH07: Evolving Skies Boost Shake 229/203 shows an unusually wide gem-mint premium between PSA 9 and PSA 10: a $36 dollar gap, with the gem mint multiplier at 9.4x. Based on the most recent PSA 10 sale of $49.99 on May 28, 2026, the math leans toward holding the 9: expected value turns negative at conservative upgrade probabilities once the resub fee is in.
PSA 10
$40.00
Last sale $49.99 on
PSA 9
$4.25
Last sale $4.25 on
PSA 8
$9.51
Last sale $9.99 on
The Spread
The PSA 9 to PSA 10 spread on Boost Shake 229/203 (SWSH07: Evolving Skies).
$36
Dollar gap, PSA 9 to PSA 10
9.4x
PSA 10 sells for 9.4x a PSA 9
Three-Outcome EV Calculator
15%
70%
15%
Defaults are conservative starting points. Adjust based on the specific slab. A borderline 9 with strong centering plays differently than a 9 with edge wear.
PSA 10 outcome (sale price minus resub minus acquisition)
$0
PSA 9 outcome (regrade, no upgrade)
$0
PSA 8 outcome (downgrade, slower sell, tied capital)
$0
Expected Value
$0
Math favors holding the 9
Where this card lands in the broader SWSH07: Evolving Skies picture: a modern-era card carrying a $36 gap between PSA 9 and PSA 10, a 9.4x multiple on the PSA 9 price.
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