The market for collectible sports mementos has taken off in recent years, with sales of rare items routinely exceeding $1 million. But valuing old sports cards and other rarities is difficult; it typically requires Internet searches and poring over paper catalogs from past auctions.

Now, noted sports collector Gary Cypres, who values his own collection at more than $20 million, thinks he has a better way to track that data. He and his son Jeremy formed Auction Data, a company that operates website PriceRealized.com.

“Now we can track the history of items and see what kinds of returns these investments provide,” said the younger Cypres.

To build the site, housed at the family’s sports museum in downtown Los Angeles, Gary Cypres contacted the auction houses, many of which agreed to license their data at no charge. His son then spent more than a year digitizing 20 years of catalogs from major auction houses. Data from recent sales is available at no charge, and historical data can be had as part of a $9.99 monthly subscription.

The website has records for approximately 700,000 transactions covering more than $1 billion in sales. About 10 percent of the sales were for Hollywood memorabilia, which the website also tracks. The plan is to continue updating the database with historical records while adding information from current auctions and private sales.

“More and more collectors are coming into this marketplace all the time,” said Dan Imler, vice president at SCP Auctions in Laguna Niguel. “Prices have been rising on a consistent basis and as it becomes more of a high-stakes venture, the need for information becomes greater.”

Game-worn jerseys have become commonplace, but ones with a special provenance attached to them – say the jersey worn by Los Angeles Dodgers pitcher Clayton Kershaw when he threw his no-hitter last year – can see significant appreciation. The information stored at the site serves as a guide for determining which collectibles have the greatest chance of being great investments. Items associated with players that have long and notable careers go for a premium.

“Players come and go, but in 50 years everyone will still know who Babe Ruth is,” Gary Cypres said.

– David Nusbaum

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