Corner the Market
Trading Card Portfolio Tracker
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
Your entire card collection—values, live eBay comps, grading math, trade analysis—organized and in your pocket.
Corner the Market is the all-in-one portfolio tracker for serious trading card collectors. Whether you collect baseball, basketball, Pokémon, or Magic — track what you own, monitor real eBay prices, and make smarter buy, sell, grade, and trade decisions.
MY COLLECTION
Add cards with full details: player, year, brand, card number, parallel, condition, purchase price, and date. Mark cards sold when you flip them. Active and sold cards stay separate, searchable, and sortable.
REAL-TIME EBAY PRICES
Look up any card's current market value using live eBay data. See the full price spread with a chart showing Q1, median, Q3, and individual sale prices — not just the cheapest listing.
WATCHLIST
Track cards you want to buy. Set a target price and see when market prices drop into your range. Monitor live eBay listings without leaving the app.
TOOLS THAT DO THE MATH
· Sale Calculator — real profit after eBay fees, shipping, and cost basis
· Should I Grade This? — compare raw vs. PSA 9 vs. PSA 10 eBay prices before you submit
· Trade Analyzer — see the real market value on both sides of any trade
· Backup & Restore — export and restore your full collection anytime
PORTFOLIO ANALYTICS
Value, total invested, win rate, unrealized and realized gains, ROI by year, brand, and condition, top performers, and a portfolio timeline chart.
SUPPORTS ALL MAJOR CARD TYPES
Baseball · Football · Basketball · Hockey · Soccer · Pokémon · Magic: The Gathering · Yu-Gi-Oh! · and more
Ratings & Reviews
The developer, Alan Niebuhr, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Alan Niebuhr
- Size
- 33.9 MB
- Category
- Sports
- Compatibility
Requires iOS 15.1 or later.
- iPhone
Requires iOS 15.1 or later. - iPod touch
Requires iOS 15.1 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © Copyright Alan Niebuhr 2026