The art market is still crackling. Christie's International PLC said Tuesday it sold $4.5 billion of fine and decorative art during the first half of the year, up 22% from the same period a year ago—and representing a record high for the privately held company based in London. Christie's total included $3.6 billion in auction sales and $828 million in privately brokered art sales. Its private sales were up 16% compared with the first half of 2013.

Rival Sotheby's said it auctioned $3.3 billion in art during the first half, up 29.4% from the year before. The New York-based auctioneer will release consolidated totals next month.