Drawdown vs population: a price fall is only a supply story if the supply actually grew
Screen 2 lists cards 30% or more below their window high, then asks whether the PSA 10 count rose in the meantime. With one population read the second column waits; here is why it is built that way.
A card that has fallen 40% has fallen for a reason, and the two usual reasons look identical on a price chart. Either demand faded, or a wave of freshly graded copies arrived. Screen 2 exists to separate them.
Two inputs, two clocks
Price is the observed daily raw market series for each population-tracked card. The window high is the highest daily reading in the observed window, and the drawdown is today's reading divided by that high, minus one. Modelled history is never used, so the window starts where the observed series starts: 18 March 2026 for the cards read on 13 September.
Supply is the PSA 10 population, compared between two dated reads at least 21 days apart. The newest count against the oldest count that clears the gap. A change under 5% counts as flat.
Why the supply column can say "one read"
Population is read by hand from PSA's published reports, monthly. The first read landed on 13 September 2026. Until a second read exists at least three weeks later, no card can show a population change, and the column says so in words rather than showing a zero that would read as "flat".
This was a design choice, not a gap. A screen that printed "supply flat" from one read would be claiming something it could not know. The logic for two reads is tested on fixture data and switches on by itself when the second read lands.
What the first read showed
Of the 99 tracked cards, six sat at or beyond 30% below their window high on 13 September 2026. The deepest was Shining Charizard #107 from Neo Destiny, at $1,495 against a window high of $3,999 on 25 March, a drawdown of 63%.
That figure is the unlimited print's series. The same day, a check on a different card found the provider's history following the 1st Edition print on the Wizards-era products; the affected cards, Shining Charizard among them, were re-pulled on the unlimited print before the screen was published. The count of cards past the threshold moved from seven to six in the repair.
How to read a row once both columns exist
A deep drawdown with flat supply is the case the screen was built to find: the price moved without new PSA 10s arriving. A deep drawdown with growing supply is the other story, and the screen will show it as plainly. Neither row is a recommendation. The screen shows which story the numbers support.