IN PLAIN ENGLISH
Card prices jump around. This is where your card has been trading lately, so the widget can show whether today's price is above or below that. It's a recent average, not a prediction or a view on what the card should be worth.
FULL DEFINITION
A collectible card's average market price over the last 90 days of its price history, times the copies you hold — the reference Fair Value Discounts compares a card with when it's set to Market reference.
EXAMPLE
Say a card's price averaged $12.00 over the last 90 days, you hold 2 copies and $1 = £0.75: its reference is 12 × 2 × 0.75 = £18.00. Worth £16.00 at today's price, it sits £2.00 (+12.5% of today's value) below its reference, so the widget lists it as a discount.
HOW IT'S CALCULATED
Reference = (average of the daily market prices for your printing over the 90 days up to its latest price) × copies × the latest stored USD→currency rate. Prices are TCGplayer's market prices as recorded by TickerMint (see Card Market Price), one a day for the last three months. Only your printing counts, never another printing's price. It needs at least 30 days of prices in the window; a newer card shows No Data until it has them. Converting at today's rate means the comparison moves with card prices, not exchange rates. Gap = reference − value today; Gap % = gap ÷ value today × 100.
Educational content only. It is not personal financial advice.