At $5 billion a year, the rare-coin market is so big that when the government lays claim to some marquee pieces in private hands, the decision makes national headlines.

Steven L. Contursi, who has owned a mint-condition 1794 Liberty dollar for the past seven years, confirmed Thursday that he sold it to the Cardinal Collection Educational Foundation of Sunnyvale for $7.85 million - setting the new world record for the Most Expensive Coin.