How to Pull Accurate Comps (Step-by-Step)

Start by nailing every attribute—set, number, variant, serial, and condition—so you only compare apples to apples.

• Set and year (e.g., 2022 Topps Chrome)
• Card number (#150)
• Variant or parallel (Refractor, Blue Wave, Image Variation, etc.)
• Serial (e.g., /150)
• Condition or grade (raw, PSA 9, BGS 9.5 true gem, SGC 10)

Use marketplaces that expose completed sales and filter aggressively to the same parallel, serial, and grade.

• In-season sports: use a 30–45 day window.
• Off-season or thin markets: stretch to 90 days for a bigger sample.

• Convert currencies to your baseline.
• Adjust for heavy coupons or promos that inflate the sale price.
• Exclude lots or obviously damaged copies if you are pricing a clean single.

Use an interquartile range (IQR) approach to clip unrealistic highs and lows before you set pricing.

1. Compute the median of cleaned sold prices.
2. Calculate Q1 and Q3; find IQR = Q3 − Q1.
3. Discard prices outside Q1 − 1.5×IQR or Q3 + 1.5×IQR.

Watch for shill bidding, charity auctions, or signature variants masquerading as base cards.

• Velocity: How many sold per week? One sale in 90 days signals fragile comps.
• Depth: How many active listings sit at your target price? Thin supply can justify a premium.

Player call-ups, trades, injuries, or award runs can shift pricing inside a single week. Pair your main lookback with a 7-day pulse to avoid stale comps.

• List price (anchor): median clean comp + 5–15% depending on market heat.
• Offer acceptance: down to median or median − 5–10%.
• Hard floor: set by your cost basis and target margin.

Archive sold links, prices, and context (condition remarks, BIN vs auction). Capture your pricing bands and reasoning for future audits.

• Raw parallel with thin sales: stretch the window and sanity-check against adjacent years or parallel tiers.
• Graded base with a large sample: weight the most recent 10–20 sales and stay within 30 days.

Straight answers to the most common comp questions.