(Bloomberg) - You'd have thought negative interest rates would fuel a boom in diamonds, antiques and fine wine, as people look for an alternative to stuffing cash under the mattress. But you'd be wrong: prices for all three are falling.

While some "collectibles" such as vintage watches, luxury handbags and old cars are holding up pretty well, others are struggling. The phenomenon of safe havens not always proving the best place to hide was explored by Gadfly colleague Nir Kaissar recently, who questioned gold, cash and real estate.

Trade in collectible treasures from minor Picassos to Patek Philippes can be equally unreliable. Of course their allure is that they're not correlated to whip-sawing financial markets, but they're never entirely disconnected from the real world. Indeed, a reason for the poor performance of some alternative asset classes is their correlation with China. Wealthy Chinese piled into high-end luxury in recent years, but the crackdown on conspicuous spending has had a huge impact on some collectibles already, as the charts below show. Others may follow.

Fine Wine

Fine wine prices rise and fall with the Chinese market. Following a tax removal in 2008, China became a big buyer of fine wine, driving prices upward, according to Justin Gibbs, director and co-founder of the Liv-ex fine wine marketplace. Similarly, austerity and curtailed gift-giving in China has pushed the market down since 2011.