Save your retirement fund by avoiding these risky investments

As retirement grows closer, these volatile stocks are best avoided.

Trying to predict the movements of individual stocks and funds is often a futile endeavor, but it gets harder when you're tracking highly volatile investments.

Many stocks, mutual funds, and ETFs are well known for share prices that jump around. That movement can be exploited in the short-term, but it's usually not helpful for long-term investors. What's more, many of the most volatile investments haven't performed well, overall.

Here are 10 stocks that are among the most volatile in the market, based on a common measurement known as beta. Most of these firms have a beta higher than their industry's average. Generally speaking, any investment with a beta higher than 1.0 is considered more volatile than average.

1. SolarCity [NASDAQ: SCTY]

I'm personally a big fan of renewable energy, but it's hard to get a handle on this stock. That's because it seems very susceptible to any and all news related to green energy, and as a relatively new company, it gets big attention for nearly every deal it makes. SolarCity hit a 52-week high last September then dove to a year low within two months. Then came a gradual climb, followed by another big dip. Long-term investors are better off waiting for SolarCity to get established before jumping in.

2. Twitter [NYSE: TWTR]

Riding the ups and downs of this stock has been like being on a wooden coaster at Coney Island. Shares rose to new heights near $60 last fall, then fell 40%, then rebounded almost all the way back, only to fall to under $30 recently. On one hand, investors see the potential from Twitter's 300 million active users. But it's also clear the company hasn't entirely figured out its business plan. (Disclosure: I own some shares of Twitter.)

3. Keurig Green Mountain [NASDAQ: GMCR]

Those single serve coffee makers were a great invention, but Keurig has had a terrible year and has been one of the most volatile stocks for the last five, according to standard deviation measurements. Last November, shares were trading at $158, but now they are near $52. Investors have become skeptical of Keurig's new products, and the company's ability to hang with new competition.

4. Oil and Gas ETFs

With oil prices hammered down in the last year, energy-related stocks have also taken a beating. But they're not just down in value — they're also highly volatile. Check any list of the most volatile ETFs over the last three years, and you'll see numerous oil and gas ETFs, including Powershares S&P SmallCap Energy Portfolio and SPDR S&P Oil & Gas Equipment & Services ETF. Energy companies including Clayton Williams Energy and Carbo Ceramics are among the most volatile in the stock market.

5. S&P High Beta Portfolio [NYSE: SPHB]

This is an ETF that tracks the S&P 500 High Beta Index, which keeps tabs on the most volatile stocks in the market. As you can imagine, its price fluctuates wildly, making it a horribly impractical product for most long-term investors. Consider that 14% of this ETF's holdings are in the highly volatile oil and gas industry.

6. Alexion Pharmaceuticals [NASDAQ: ALXN]

What to make of a stock that goes from a 52-week low to a 52-week high within two months? What to make of a stock that pulls off such a swing twice in one year? Alexion has a beta figure of 1.28, which is 50% higher than the average in the biotech industry. Unless you are Nostradamus and can predict these swings, stay away.

7. TripAdvisor [NASDAQ: TRIP]

In the last year, few companies have been more volatile. The popular travel website has seen shares drop 21% in the last 52 weeks, but with wild swings during that time. Some investors may have done well with TripAdvisor stock, depending on when they sold. But trying to predict the ups and downs is a fool's game.

8. Zillow [NASDAQ: Z]

The provider of real estate information was trading at $148 about a year ago. Now shares are at $75 a piece. Investors have endured some big price swings in recent months, including a 14% single-day drop back in March. Zillow has a beta of 1.4, placing it in the top third of most volatile stocks in the tech industry.

9. Yelp [NYSE: YELP]

Shares of this online platform for business reviews have been less volatile this year than in years past, but that's only because they've steadily gone down. Shares have dropped more than 60% since a 52-week high last September.

10. Casino Stocks

Look to Las Vegas for some volatility. Wynn Resorts has been one of the more volatile stocks in the last three years, and shares are down more than 40% this year. Caesar's Entertainment has also been all over the place, trading at $17 last November and then dropping to $3.30 this past June. You may have better luck at the blackjack table than you would trying to anticipate the movements of these stocks.

This article is from Tim Lemke of Wise Bread, an award-winning personal finance andcredit card comparison website.