Forget gold. Classic cars are the new hot investment.

For rich people seeking new places to put their money, maybe one more fun than mutual funds and less risky than tech startups, one asset class is beating out all the rest: Classic cars. Real estate firm Knight Frank put out its Luxury Index on Friday, which tracks a basket of collectible items that serves as a good proxy for how good wealthy people are feeling about their situations in life. Known as the KFLII, it kept rising fairly steadily through the recession, and is now beating the global s...