Image source: Getty Images.

Smart investors think for themselves. But that doesn't mean you can't get good ideas from those who've already demonstrated track records of finding successful investing ideas. Often, looking at stocks billionaires have bought can give you a lead on what can be a lucrative investment for your own portfolio. With that in mind, we've found three stocks that have hit billionaires' radar screens recently, and below, you'll find some information on them that you can use to decide whether they're smart ideas for you.

A pipeline to wealth

Dan Caplinger: When billionaire Warren Buffett starts buying stock, it's worth paying attention, and one of the Oracle of Omaha's most interesting buys recently has been pipeline company Kinder Morgan (KMI -0.86%). Kinder Morgan stock has taken a huge hit because of the drop in oil and natural gas prices, but the energy giant is a leader in the pipeline industry, claiming the status as the largest energy infrastructure company in North America because of its unparalleled natural gas pipeline network. It is also the largest transporter of petroleum products and carbon dioxide, and leads the industry as a key terminal operator. With control of the only pipeline currently connecting the Alberta oil sands region to Canada's west coast, Kinder Morgan has many unique characteristics.

Image source: Kinder Morgan.

Kinder Morgan shares have fallen in large part because of substantial debt and concerns about its ability to maintain that debt. However, continuing low interest rates should ease the burden for Kinder Morgan, and a bounce in crude oil prices could spur further production that could increase volume for the pipeline giant over time. Kinder Morgan isn't a sure bet, but it's easy to understand why billionaires like Buffett are looking at the stock as a deep value play.

Targeting a massive market

Todd Campbell: One company billionaires are buying that has become increasingly intriguing to me is Flexion Therapeutics (FLXN).

Flexion Therapeutics is developing Zilretta, a therapy for knee pain in osteoarthritis patients. Earlier this year, the FDA told the company that previously reported phase 3 results could serve as the basis for a New Drug Application, and Flexion Therapeutics is expected to file that application soon.

If that application eventually leads to an approval, Zilretta could quickly displace corticosteroids, which are used to control knee pain in 5 million patients every year.

In trials, Zilretta delivered a 50% reduction in pain from baseline during the 12-week study. Importantly, patients experienced pain relief throughout the period, suggesting Zilretta could be a better alternative than corticosteroid shots. Typically, pain relief provided by corticosteroid shots fades within a few weeks.

The potential to reshape treatment in this big indication has already gotten the attention of some of Wall Street's biggest investors. In the first quarter, Millennium Management and Renaissance Technologies, two Goliath hedge funds piloted by billionaire investors, bought 125,414 shares and 124,500 shares of Flexion Therapeutics, respectively. There's no telling if they still own those stakes, but their interest adds conviction that Zilretta could eventually be a winner.

Looking for a huge turnaround

Daniel Miller: If you're looking for a high-risk, high-reward type of stock -- and one that at least one billionaire hedge fund manager is buying -- look no further than Valeant Pharmaceuticals Intl Inc. (BHC 2.43%).

It's been a brutal year for the company, whose shares have plunged nearly 90% after its aggressive and undisciplined use of leverage to acquire companies, and revelations of unethical practices of hiking prices on its products.

Image source: National Institutes of Health Image Gallery.

Amid the Valeant's plunge in stock price, and despite many analysts walking away from the stock, Okumus Fund Management nearly doubled its stake in the company. At the end of March, Okumus Fund Management owned 3.72 million shares, worth $97.90 million at the time.

Now the recently refreshed board of directors and new CEO Joseph Papa have quite the task at hand to reduce debt, which disables the company from investing as much into assets and new product development. Also, as part of the debt reduction phase, the company is going to sell assets, which could rope in less-than-expected amounts and further pressure the already beaten-down stock price.

If the company can rebound from its tarnished image and walk the fine line between selling appropriate assets at good prices, the rest of the equation is favorable. That's because Valeant has an extensive and diverse portfolio of products, and products that face little competitive risks in the near term. Another catalyst: rising incomes and demand for healthcare in Central Europe, as well as Latin America, should benefit the company's business.

There have been a couple of bullish signs this week, however minor they may seem: a 15% pop thanks to Walgreens' willingness to work with Valeant on their distribution deal, and a reported spike in call options that expired on Friday, July 8.

Again, this is a high-risk, high-reward type of investment, and bulls would have to place a lot of faith in the newly appointed CEO. It is too high-risk for me, but at least one billionaire disagrees.