The Knight Frank Luxury Investment Index, which tracks the price growth in the major categories of collectibles, found that wine has replaced classic cars as the top collectible. Thanks to strength in Bordeaux, Burgundy and northern Italian wines, collectible wine prices surged 25 percent over the past year and are up 61 percent over the past five years.

Fine wine is now the best-performing collectible of the world's wealthy collectors, with values soaring 25 percent over the past 12 months, according to a new report.

The jump follows a boom and bust in fine wines after the financial crisis, when Chinese buying exploded and then cooled. Now that prices have stabilized and the Chinese economy remains strong, buying has picked up again. Wealthy Chinese are not only scooping up the fine wines, but they've also developed a taste for vineyards, snapping up more than 100 chateaux in France's Bordeaux region.

But wine prices are also being driven by strength from strong economies in the U.S., Europe and the rest of Asia. And Chinese buyers are becoming more expert buyers.

"After the crisis, the Chinese buyers were buying high-value wines not because they liked them, but because they perceived those wines to be the ones to buy," said Andrew Shirley, who compiled the report for Knight Frank. "We saw that bubble pop. Now the Chinese wine buyers are more connoisseurs."

Sotheby's led the global wine auction market last year, with total sales up 22 percent over 2015. It's sale of wines from the cellar of William Koch fetched $22 million, and a 10-bottle lot of 1945 Chateau Mouton Rothschild went for $343,000 – way above its $120,000 estimate.

At the same time, classic cars are taking a spill. After dominating the collectible list for years, with hair-raising price increases, classic car prices grew only 2 percent over the past 12 months, according to Knight Frank. They fell to sixth place on the ranking of collectibles.

"I think cars are in for a period of flatter growth," Shirley said.

Art ranked second after wine, reporting growth of 7 percent. But given the recent strength of the market and some important masterpieces expected to come up for sale in the fall, art could end the year at the top spot.

"Art buyers have become more selective," Shirley said. "But I wouldn't be surprised to see art end the year on top."