Ask Matt: What have been the year's worst IPOs?

• Top-performing IPOs this year include Sprouts and Noodles
• But there have been many disappointments%2C too
• Propensa is the year%27s worst IPO

USA TODAY markets reporter Matt Krantz answers a different reader question every weekday. To submit a question, e-mail Matt at mkrantz@usatoday.com.

Q: What have been the year's worst IPOs?

A: Potbelly. Noodles & Co. Sprouts Farmers Markets. These are all the huge winning initial public offerings this year. These are the deals most people like to talk about because they've all more than doubled from their IPO prices.

But investors will have a tougher time finding others bragging about buying into IPOs that didn't fare so well this year. And there have been plenty of dogs in what's been a pretty solid year for IPOs.

All three of the worst performing IPOs in 2013 so far have been health care deals, says IPOScoop.com. Propensa Holding, a biotech company working on treatments for diseases including muscular dystrophy, is down more than 66% from the $13 a share offering price. The company disappointed investors in September when saying one of its top drugs in development didn't make it to late-stage clinical trials.

Following Propensa is LipoScience, a maker of diagnostics to test patients, which has seen its shares fall 48% from its IPO price of $9 a share. The company told investors in August that demand for its diagnostics test wasn't growing as fast as its costs were. The company lost $2.4 million in the quarter ended in June. And behind LipoScience as the worst IPO of the year is KaloBios, down 48% from its $8 a share IPO price.

These big disappointments in the IPO market are a reminder to investors that making money on unproven stocks isn't as easy as it might seem. Even though the IPO market is raging, and most IPOs are doing well, there are still the laggards.