1.  Netflix

netflix fire
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  • Ticker: NFLX (NFLX)
  • YTD gain: 92%

If orange is the new black, Netflix shares might be the new gold.

At least that's the kind of year Netflix (NFLX) stock is having. Thanks to impressive subscriber growth, the streaming service's shares have skyrocketed 91%. That easily makes them the best performer in the S&P 500 during the first half of 2015.

Netflix is so hot that last week it pulled an Apple (AAPL) and split its stock -- seven times! The move makes Netflix shares easier for everyday investors to afford. Instead of costing nearly $700, a share will cost a little less than $100.

Related: Do you need to be a 'Daredevil' to buy Netflix stock?

Stock split or not, Netflix is very expensive. It's trading at nearly 500 times 2015 earnings. That's the third highest in the S&P 500. Maybe that's why legendary investor Carl Icahn just exited his highly profitable position in Netflix. Others believe Netflix will stay white hot. Brokerage BTIG boosted its target on the stock to $950.

First published June 30, 2015: 1:07 PM ET