Grexit concerns, Puerto Rico debt problems and the China meltdown were chasing the U.S. economy, when it entered the second half of the year. Luckily within weeks, the Greece bailout agreement, a rebound in the Chinese stocks -- and a spate of upbeat economic data and strong earnings reports, especially from Google (GOOGL - Analyst Report) and Amazon (AMZN - Analyst Report) -- chased away all fears.

If this wasn’t enough, the Fed injected fresh optimism into the economy by keeping its stance on interest rates unchanged. But of course, the central bank has indicated a raise the interest rates sometime later on in the year given solid job gains and an improving housing market.

This is especially true as the first quarter slump in the U.S. seems to have been tided over with a 2.3% economic expansion in the second quarter. Further, stepped-up economic and business activities, rising consumer spending and a flurry of mergers and acquisitions are fueling growth in the stock market.

The Nasdaq Composite Index hit another record high on incredible performances from some of the big tech players, gaining 2.3% over the last one-month period. Meanwhile, the S&P 500 gained 1.5% while the Dow Jones saw a modest decline of 0.1%. Given this, many corners of the equity space have seen smooth trading to start the second half and have piled up impressive gains from a one-month look.

Of these, we highlight the five best-performing, top-ranked stocks that not only crushed the broad market returns but also have the potential to outperform through the rest of the second half. For this, we have used our Zacks stock screener where we scanned for stocks with a Zacks Rank #1 (Strong Buy) or #2 (Buy) and a Growth Style Score of B or better. This is quite a combination to look for in stocks, especially for investors beefing up their portfolio amid volatility and uncertainty.

Our Growth Style Score condenses all the essential metrics from a company’s financial statements to get a true sense of the quality and sustainability of its growth. Our research shows that stocks with Growth Style Scores of ‘A’ or ‘B’ when combined with a Zacks Rank #1 or #2 offer the best investment opportunities in the growth investing space.

Here are the five stocks that are surging since the start of 2H and are expected to continue their strong run through the second half:

Anacor Pharmaceuticals (ANAC - Snapshot Report) – Up 88.3%

Anacor is a biopharmaceutical company engaged in discovery, development and commercialization of novel small-molecule therapeutics derived from its boron chemistry platform. It saw a whopping 88% rise over the past month and is expected to deliver earnings growth of 45% for this year compared to an earnings decline of 1.5% for the industry. Revenues are expected to grow 294.1%, which is much above the industry average of 4.1%.

The stock has a Zacks Rank #2 and a Growth Style Score of ‘A.’ Further, Anacor falls in a solid industry, having a Zacks Rank in the top 37%.  

Google Inc. (GOOGL - Analyst Report) – Up 21.7%

Google is a technology company that provides a web-based search engine through its website. The company offers a wide range of search options including web, image, groups, directory and news searches. It is expected to deliver solid earnings and revenue growth of 12.6% and 14.7%, respectively, this year compared with industry average growth of 9.2% for earnings and 9.8% for revenues.

The stock has gained 21.7% so far in the second half and is expected to continue to rise given that it has a Zacks Rank #2 with a Growth Style Score of ‘B’ and a solid industry Rank in the top 39%.

Amazon.com Inc. (AMZN - Analyst Report) – Up 20.9%

Amazon.com is the world leading online retailer in North America and internationally. It has an earnings estimated growth rate of 329.9% and revenue growth rate of 18.6% for this fiscal year. This is well above than the industry averages of 17.1% and 1.1%, respectively.

Shares of AMZN surged nearly 21% over the past one-month period. This trend is likely to continue as the stock has a Zacks Rank #1 with a Growth Style Score of ‘B’. However, the Internet commerce industry in which Amazon falls does not seem good at present as the industry has a Zacks Rank in the bottom 40% at the time of writing.    

Allegiant Travel Company (ALGT - Snapshot Report) – Up 16.0%

Allegiant Travel is a leisure travel company focusing on linking travelers in small cities to world-class leisure destinations such as Phoenix, AZ, and the Florida cities of Fort Lauderdale, Orlando and Tampa/St. Petersburg. The company is expected to deliver earnings growth of 89.4% and revenue growth of 11.2% for this year. This seems very solid given the industry averages of 59.4% for earnings growth and flat revenue.

This Zacks Rank #1 stock with Growth Style Score of ‘A’ is up 16% to start the second half and has a solid industry rank in the top 37%.

ICON Public Limited Company (ICLR - Snapshot Report) – Up 15.8%

This Zacks Rank #2 company is a global provider of outsourced development services to the pharmaceutical, biotechnology and medical device industries. It gained nearly 16% in the past month and has an estimated earnings growth rate of 33.8%, substantially above the industry average of 21.6%. Revenue is expected to grow 7.9% versus the industry average of 5.5%.

ICLR has a Growth Style Score of ‘A’ and falls in the solid industry having a Zacks Rank in the top 40%.