FANG stocks have been exploding lately, even as the stock market as a whole has struggled to recoup losses from earlier in the year.

FANG, an acronym coined years ago by TheStreet's Jim Cramer, encompasses Facebook Inc. (FB - Get Report) , Amazon.com Inc. (AMZN - Get Report) , Netflix Inc. (NFLX - Get Report) and Alphabet Inc. (GOOGL - Get Report) . While those stocks have performed with impressive strength in recent history, tech sector gains aren't limited to just FANG.

The New York Stock Exchange's FANG+ Index includes the aforementioned FANG names, plus other heavy hitters Apple Inc. (AAPL - Get Report) , Twitter Inc. (TWTR - Get Report) , Baidu Inc. (BIDU - Get Report) , Nvidia Corp. (NVDA - Get Report) and Tesla Inc. (TSLA - Get Report) . That index has climbed 23% so far this year, earning the group of stocks an annualized return of 67% since early last year.

The group has even now outpaced the gains of the tech-heavy Nasdaq Composite benchmark index in its final two years of the dot-com bubble, according to Bloomberg data. During the last two years of that rally, the Nasdaq gained 66%.

The NYSE FANG+ index has also outperformed the broader market in current market conditions. Even as the Dow, the S&P 500, the Nasdaq and the Russell 2000 fell on Wednesday, the tech index was marked 1% higher by the market close.

Wall Street analysts expect earnings in the group to advance 22% over the next three to five years, Bloomberg data showed. That would be double the consensus expectation for the broader S&P 500.

Valuations have also soared. The companies in the FANG+ Index trade at almost three times the average of the market at large on a valuation basis.

Bubble or just betting on strong fundamentals? We'll find out shortly, for sure. 

Facebook, Amazon, Alphabet, Apple and Nvidia are holdings in Jim Cramer's Action Alerts PLUS Charitable Trust Portfolio . Want to be alerted before Cramer buys or sells the stocks? Learn more now.

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