Take Monster Beverage, for instance: Gross sales jumped 9 percent year-over-year in April and May, and sales look "increasingly favorable in June," Stifel analysts noted. There was cause for concern after caffeinated beverages came under scrutiny by regulators —the company reported a mere 6.5 percent increase in sales during the first quarter after eight consecutive quarters of double-digit year-on-year revenue growth—but business clearly picked up again this spring. Monster Beverage's revenue is expected to grow 10 percent this year, according to data compiled by Bloomberg. That's slower than the 21 percent jump in 2012 and 30.6 percent in 2011, but still impressive. The company did not respond to a request for comment.