The Nasdaq Composite Index has been hitting record highs and logged in gains for seven consecutive months, a streak not seen since early 2013.

The astounding surge in FANG stocks (Facebook (FB - Free Report) , Amazon (AMZN - Free Report) , Netflix (NFLX - Free Report) and Alphabet is driving the index. These stocks have gained around 30% in the year-to-date timeframe and make up for 40% weight in the index. Additionally, Apple (AAPL - Free Report) , joined the “FAANGtastic five,” having returned 33%.

A combination of factors like improving global fundamentals, strong corporate earnings, a rising interest rate scenario, Trump’s proposed corporate tax reform, and the emergence of cutting-edge technology are acting as key catalysts to these stocks.

Consumer discretionary and industrials stocks in the index are also gaining on accelerating economic growth and rising consumer confidence. Stability in oil prices, pick up in activities in most part of the world as well as improved global sentiments especially after the French election, which has erased fears of a populist rise, have added to the strength.

As a result, PowerShares QQQ (QQQ - Free Report) , which serves as a proxy for the index, climbed 21.3% this year so far. While these tech giants no doubt delivered outstanding performances, a few gained more than 50% and emerged as the real winners though they have slight exposure to the fund’s portfolio.

Let’s take a closer look at the fundamentals of QQQ and the five best-performing stocks in the ETF with their respective positions in the fund’s basket.

QQQ in Focus

This ETF provides exposure to the 107 largest domestic and international non-financial companies listed on the Nasdaq by tracking the Nasdaq-100 Index. QQQ is one of the largest and the most popular ETF in the large cap space with AUM of $52.7 billion and average daily volume of around 20.4 million shares. It charges investors 20 bps in annual fees. The fund has a Zacks ETF Rank of 1 or ‘Strong Buy’ rating with a Medium risk outlook.

Best Performing Stocks of QQQ

Vertex Pharmaceuticals (VRTX - Free Report) : The stock has surged 76.7% so far this year and carries a Zacks Rank #3 (Hold) with a VGM Style Score of B. Though the company has seen negative earnings estimate revision of eight cents for this year over the past three months, its earnings are expected to grow a whopping 479.22% compared with the industry average of 6.05%. The stock accounts for just 0.5% share in QQQ.

Tesla (TSLA - Free Report) : This stock makes up for 0.7% allocation in the fund’s basket and has delivered incredible returns of 59% so far this year. However, the stock has seen negative earnings estimate revision from a loss of $2.73 to a loss of $7.42 over the past three months for this year, reflecting year-over-year earnings decline of 42.97%. Further, Tesla has a Zacks Rank #5 (Strong Sell) and a VGM Style Score of F.

JD.com Inc. (JD - Free Report) : The stock has gained about 58.5% in the year-to-date timeframe. It has seen solid earnings estimate revision from a loss of 5 cents to earnings of 8 cents over the past three months for this year with an expected earnings growth rate of 120%. This is much higher than the industry average of 20.82%. JD.com currently has a Zacks Rank #2 (Buy) and a VGM Style Score of A. The stock makes up for 0.5% share in QQQ.

Wynn Resorts Limited (WYNN - Free Report) : This stock has surged 54.1% so far this year and has 0.2% exposure in the fund’s basket. It has seen solid earnings estimate revision of $1.28 over the past three months for this year with an expected earnings growth rate of 36.23%, much higher than the industry average of 17.83%. Wynn Resorts has a Zacks Rank #1 and a VGM Style Score of D.

CSX Corporation (CSX - Free Report) : This stock accounts for 0.75% of assets in the fund’s basket. It has gained 50.4% in the year-to-date timeframe and has seen positive earnings estimate revision of 26 cents over the past three months for this year. As a result, its earnings are expected to grow 26.47% compared with the industry average of 11.04%. CSX Corporation has a Zacks Rank #1 and a VGM Style Score of B.