XY - Steam Siege Secret (STS) carries a total slabbed market cap of $3.2M as of Nov 13, 2026. TCGBerg tracks a fair value for 10 card and grade combinations in the set. Gardevoir EX #116 · PSA 10 anchors the set at 55.5% of its total cap.
Historical context
Released in 2016 as a EN release.
Market overview
Cap is concentrated: the largest card-grade position is 55.5% and the top 5 make up 96.8% of set cap. The set's cap-weighted fair-value confidence is high (78/100). It has seen 97 graded sales over the trailing 30 days.
Frequently asked
How much is a complete XY - Steam Siege Secret set worth?
One Near Mint copy of each XY - Steam Siege Secret card costs about $149 (the cheapest printing of each, 2 of 2 cards priced as of Nov 13, 2026). The most valuable is Gardevoir EX #116 at $113.
What is included in the XY - Steam Siege Secret card list?
This list covers 2 catalog printings. Editions and finishes can have separate entries for the same card number. Prices appear where valuation or sales evidence is available; an unpriced entry does not mean the card is worth zero.
How do I compare XY - Steam Siege Secret card prices?
Match the card number, printing and condition before comparing values. Use raw condition prices for ungraded copies, and the same grading company and grade for slabs. Open a card to check the available price history, recorded sales and sales evidence.