Four of the jumps were driven by mergers and acquisitions announcements, but the majority of the surges came after blowout earnings results.
On May 25, 2017, shares of Best Buy rallied more than 21% after the company posted unexpected sales growth in same store locations. The jump in sales was attributed to an unexpected surge of shoppers spending their tax refunds on electronics in the first quarter.
Biotech company Vertex Pharmaceuticals jumped more than 21 percent on July 19, 2017 after the drugmaker reported an improved response in patients suffering from cystic fibrosis. Vertex said its three-drug cocktails boosted a measure of lung function in patients with cystic fibrosis by 9.6 percentage points or more, which crushed Wall Street expectations for the drug combination.
Power producer NRG Energy on July 12, 2017 announced a transformation plan to raise $2.5 billion to $4 billion by divesting 50% to 100% of its renewable energy business, aiming to remove $13 billion in debt from its balance sheet. The news sent the company stock soaring a whopping 29% that day.
On Oct. 30, 2018, Under Armour shares rallied nearly 28% after it reported blowout quarterly earnings due to a spike in sales overseas. The athletic apparel company had been undergoing changes to trim excess inventory and cut costs amid fierce competition in the space. The strong results came as a relief that Under Armour’s turnaround efforts were paying off after years of patchy sales.