George Soros didn't amass his estimated net worth of more than $25 billion by making bad stock picks. Through the years, the billionaire investor has poured money into plenty of huge winners.

This year is no exception. These five best-performing Soros stocks have generated gains of at least 46% so far in 2017: Extreme Networks (NASDAQ:EXTR), Wayfair (NYSE:W), MakeMyTrip Limited (NASDAQ:MMYT), Tesla (NASDAQ:TSLA), and Genco Shipping & Trading (NYSE:GNK). Here's how George Soros racked up huge returns from these stocks this year.

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Extreme Networks: Acquisitions and earnings powering the stock

Extreme Networks stock has soared nearly 85% year to date. The networking hardware and software provider has had several catalysts that propelled its share price higher over the past few months.

In early March, Extreme Networks received a boost after announcing that it planned to acquire the networking business of Avaya, which filed for chapter 11 bankruptcy. Later in the month, the stock jumped again on an acquisition -- this time with Extreme Networks announcing that it was buying the data center technology business of Brocade Communication Systems. Most recently, the share price shot up after the company reported strong third-quarter earnings on May 4.

Wayfair: Beating expectations

Wayfair's share price started off 2017 with some nice, but unspectacular, gains. The online home furnishing retailer's CEO reassured investors that consumer spending appeared to be stronger than thought earlier. By late April, Wayfair stock was up more than 30%. Then the company reported its first-quarter results on May 9, prompting its share price to take off. Wayfair stock is now up more than 80% in 2017.

What excited investors so much about Wayfair's first-quarter update? The company reported a loss for the quarter, but it was much better than analysts expected. Revenue grew robustly. Even better, Wayfair projected higher revenue for the second quarter than Wall Street was modeling. 

MakeMyTrip: Making Soros' year great early on

MakeMyTrip stock generated a big return for George Soros early in the year, with shares up more than 50% by the end of January. The India-based online travel company's stock price is now up more than 70% year to date.

The early success for the stock came in part from MakeMyTrip's announcement in January that it had completed its merger of the ibibo Group. This merger created one of the largest travel groups in India. MakeMyTrip also reported strong revenue and earnings growth for the first quarter. The momentum from these announcements kept the stock moving higher throughout the following months, even though MakeMyTrip's shares pulled back in May after the company announced an equity financing round.

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Tesla: Driving higher on good news

Tesla stock is up more than 50% so far in 2017. And that's after a significant drop in late February after the innovative car company reported strong financial results but failed to satisfy investors and after receiving a downgrade from Goldman Sachs. 

Overall, though, the news has been quite good for Tesla this year. The company announced that it's expanding its charging network to more than 10,000 Superchargers by the end of 2017. Tesla also provided an update stating that it will unveil its first electric semi truck in September. 

Genco Shipping & Trading: Thank-you cards needed for Wall Street firms

Perhaps the most unlikely winner among George Soros' best-performing stocks of 2017 is Genco Shipping & Trading. The shipping company appeared to be fighting for survival earlier in the year, but the stock has gained more than 45% year to date. 

How did Genco do it? To paraphrase the Beatles, with a little help from its friends. Wall Street investment bank Morgan Stanley said in March that dry bulk shipping stocks were ready to rebound. Despite a dismal earnings report from Genco, other Wall Street firms said that its share price was destined to go higher. And it did, thanks to their glowing projections. 

Another common denominator

There's one other thing that these five stocks have in common other than being top performers for George Soros in 2017: They're all losing money.

Several of them are improving from a financial perspective, though. Still, I wouldn't count on any of these stocks being at the top of Soros' list after this year (although Tesla continues to practically defy gravity with its sky-high valuation). Finding stocks of companies with solid business models and growing earnings is probably the better option for investors who aren't billionaires yet. 

One mistake that many investors make, no matter how experienced, is selling certain investments they should have held onto. We asked three of our analysts what stocks they regret selling, and here is what they had to say.

Matt Frankel: One stock that I deeply regret selling too early was Tesla Motors (NASDAQ:TSLA). I bought in shortly after the IPO, when the stock was trading in the low $20s, and sold when it popped into the $50s in April 2013 thinking I had made a great move.

At the time, the Model S was just gaining traction, and while the reviews were good, it still remained to be seen whether or not Tesla could actually be a profitable company. Well, I think we all know how that played out.

Although I regret selling too soon, I did learn a very valuable lesson from the experience. Tesla was a company I believed in from the start, and on a long-term basis. I completely entered the investment planning to hang on to my shares forever, and I let the prospect of a quick gain cloud my judgment. Nothing had changed in my feelings on the company – it still seemed cheap relative to its long-term potential, and everything was still on the right track.

Regrets like this remind me why it's so important to always think long-term when investing. If you chase short gains, like I did with Tesla, you're more likely to leave a whole lot of your potential profits on the table.

Dan Dzombak: One stock I regret selling is Melco Crown Entertainment (NASDAQ:MPEL). Melco owns casinos in Macau, the Mecca of gambling for China and South East Asia. I purchased Melco in 2008 in the depths of the financial crisis for $3 to $4 a share when you could buy the company for below its understated book value as the whole gambling industry was in crisis around the world.

Melco's assets included one of the newest casinos in Macau, the Crown Macau, as well as the City of Dreams casino which was scheduled to open June 1, 2009. Macau is just a short flight away from the whole population of China which provided major growth opportunities going forward for Macau as it is the only place in China allowed to have casinos. Further, the government of Macau had announced a hold on new gambling licenses providing a competitive advantage to operators with projects already licensed, which included Melco, providing the company with a large moat.

As the world economy rebounded in 2010 and 2011 on the strength of China, Melco's casinos took off as did the stock. I held onto the stock until early 2013 and sold it around $20 per share to focus on other opportunities as signs pointed to China's economy slowing and the country being in a massive debt bubble. I sold despite Melco looking reasonably valued for a company with some of the best assets in a market that will undoubtedly continue to do very well over the next 10 and 20 years.

Since I sold Melco, the stock doubled again and started paying a dividend. My mistake was selling a reasonably valued stock because of macroeconomic fears that would have taken a few years to play out anyway.

Melco has now come back to $25 a share as gambling revenues are way down in Macau. There is still lots to like about Melco and you may find me owning the shares again sometime soon.

Leo Sun: One stock I sold too early was Visa (NYSE:V). I bought shares on the first day of trading in March 2008 for around $60. The stock slid to the upper $40s and mid-$50s during the nadir of the financial crisis, but I neither sold the stock nor bought more shares.

Instead, I held onto Visa, and it eventually soared as high as $96 in 2010 thanks to robust earnings. But then the news regarding swipe-fee limits hit, and both Visa and MasterCard plunged on fears that their bottom lines would be crushed. Visa bounced back briefly to the mid-$70s, so I sold my shares for a minor gain. But if I had simply done nothing, I could have ridden it to $260.

I initially invested in Visa for two reasons: it had great margins because it only processed payments, and I liked the low risk business model where its partner banks shouldered the risk of defaults. The swipe fee drama blew over with several major settlements, and Visa's profit margin -- which I thought would decline -- surpassed its 2008 and 2009 levels. Lesson learned -- don't prematurely sell a solid stock on a few negative headlines.