A murmur of admiration arose around the room when Beijing-based Yu Kin-po won bids for three artworks at Sotheby’s autumn auctions in Hong Kong last October.

The bill for the pieces, including Wu Guanzhong’s 1983 painting Climbing Vines On Wall,  came to HK$9.1 million.

Six months later, the artworks remain with Sotheby’s. On April 13, Yu’s name appeared in a High Court writ. The auction house is accusing Yu of failing to pay the total purchase price within five days and collecting the works 30 days after the sales, as contractually required, and is seeking payment plus interest.

It’s the first time in nearly three years that Sotheby’s has taken someone to court in Hong Kong. Industry insiders say auction-related lawsuits on the mainland and in the city have become more frequent in the past decade as China’s art market grows more active – it’s now the world’s second-largest according to a report by the European Fine Art Foundation.  But regulation has yet to catch up with the expansion, and the industry is calling for a revamp of auction laws.

“China needs to tighten regulations to improve the situation,” says Hu Yanyan,  president of China Guardian Auctions  and its Hong Kong arm. On the mainland, cheats block those who play by the rules and damage the industry’s development in the long run, she says.