With stocks hovering around all-time highs, many are wondering if equities are the next great bubble getting ready to burst. But stocks aren't the only things that look frothy: There are a lot of other asset classes that sure look like bubbles.
We've compiled a list of the assets that analysts now believe are flashing the warning signs of over-inflation.
What the experts say: "The cost of college textbooks has been rising at almost twice the rate of general CPI inflation for at least the last 30 years," according to Mark J. Perry, American Enterprise Institute. "As Glenn Reynolds reminds us, 'a process that cannot go on forever, won't,' and the college textbook bubble is certainly one of those processes."
Warning stat: First tier cities Beijing and Guangzhou saw home prices rise 3.1 percent in February, the biggest jumps in the country. Meanwhile, entire towns will go up in China with no inhabitants. These are China's notorious "ghost cities."
Warning stat: The "crypto currency" now trades at $63 -- double what it was at the beginning of March.
What the experts say: "In hindsight, the people who bid the price of Bitcoins up to $30 in 2011 may not have been so crazy after all. It just took the broader market, including me, a couple of years to catch up with them," according to Ars Technica's Timothy B. Lee.
Warning stat: Investors recently bid a record $3.16 for each dollar of the $2.011 trillion in bonds the U.S. government auctioned in 2012, Bloomberg says.
What the experts say: "Long-term interest rates are now unsustainably low, implying bubbles in the prices of bonds and other securities," warns economist Martin Feldstein. "When interest rates rise, as they surely will, the bubbles will burst, the prices of those securities will fall, and anyone holding them will be hurt."
Warning stat: American farmland prices continue to grow at a blazing hot double-digit rate. An industry group recently forecast that values could surge 15 percent to 20 percent in 2013.
What the experts say: "It doesn't have all the hallmarks of a bubble," according to Robert Shiller. "One of them is most people have never heard of it. In my view of a bubble, it's something that gets people excited. Well, some people are excited, but most people don't even know about it."
What the experts say: "The real question in my mind is, 'Are we possibly off to the races again?'" asked economist Robert Shiller. "I think in cities like Phoenix and San Francisco, we might be seeing something pretty big developing. People there are very speculative-minded."
Warning stat: Health care spending has grown 2.5 times faster than incomes over the past 30 years.
What the experts say: "The health care system in the U.S. reminds us somewhat ominously of the bubble in housing finance, a 'public/private partnership,'" says Citi's Steve Wieting. "Housing consumption still receives strong tax preferences, as does health insurance (reflecting underlying health care consumption). Most aptly, prior to quasi-nationalization, housing GSEs earned private profits from public subsidies for housing, as do U.S. health care providers."
Warning stat: Europe stabilized after ECB president Mario Draghi said, "Within our mandate, the ECB is ready to do whatever it takes to preserve the euro. And believe me, it will be enough."
What the experts say: "To us the key word about the post summer 2012 Euro Area asset boom is that most of it is a bubble, and one which will burst at a time of its own choosing, even though we concede that ample liquidity can often keep bubbles afloat for a long time," warns Citi Chief Economist Willem Buiter.
Warning stat: Prices are up 47 percent year-over-year, and are sitting at an 8.5 year high of $432 per 1,000 board fee.
What the experts say: "Signs of a housing bubble in the world's most populous nation may force the Chinese government to take measures to 'draw air' out of the rising housing market and to clamp down on construction lending, which would likely put a significant dent in the demand for building materials such as Lumber and Copper," according to Mike Zarembski, OptionsXpress.
What the experts say: Jeff Gundlach notes that not only have wages not increased commensurate with tuition inflation, wages have actually been falling. "What have all these soaring tuition costs got you?" asked Gundlach rhetorically.
Warning stat: Craft beer production surged 15 percent year-over-year in 2012.
What the experts say: Boston Beer Co. founder Jim Koch says most stores have reached their limit for carrying new breweries, and that too many breweries are making similar beers without adding anything to the market.
Warning stat: Canadian home prices mirrored the U.S. housing rally. However, Canadian prices never fell. A recent Canadian Housing Affordability study says the country's home market is 10 percent overvalued.
What the experts say: "I worry that what is happening in Canada is kind of a slow-motion version of what happened in the U.S," said Robert Shiller.
What the experts say: "What we find is that Bernanke does not have nearly as great a track record on inflation as he thinks he has. Greenspan could not see that the housing market was an inflated bubble. Evidently Bernanke cannot see that the stock market is an inflated bubble."