(Read More: See the Day's Top Percentage Winners & Losers)
Activision Blizzard - The videogame maker reported first-quarter profit of $0.17 per share, six cents a share above estimates, while its revenue also came in above analysts' consensus. However, it gave a cautious outlook for the remainder of the year because of slowing "World of Warcraft" game results, as well as concerns about updates to videogame consoles by companies like Nintendo, Microsoft, and Sony.
Microsoft - Microsoft has named Amy Hood, the head of finance for its Office division, as its new chief financial officer.
Monster Beverage - Monster earned $0.37 per share for the first quarter, missing estimates by nine cents a share, while revenue also came up short. The energy drink maker saw higher operating expenses, as well as negative impact from foreign currency transactions.
Transocean - Transocean reported first-quarter profit of $0.93 per share, excluding certain items, seven cents a share below estimates, with revenue coming up shy of consensus, as well. Equipment problems prevented Transocean's oil drilling rigs from operating for various periods of time during the quarter.
Sony - The electronics giant earned $948 million for the fiscal year ending March 31, its first annual profit in five years. Its results were helped by a weaker yen that boosted its overseas profits.
Barnes & Noble - The company is considering a Microsoft offer to pay $1 billion for the assets of its Nook division, according to TechCrunch.
Costco Wholesale - The warehouse retailer reported a 4 percent increase in April same-store sales, below analysts' estimates of 4.5 percent. Costco sales were impacted by lower fuel prices and the tronger dollar.
Tesla Motors - The electric car maker reported the first quarterly profit in its history and raised its sales outlook, saying sales could will reach 21,000 this year. Goldman Sachs has downgraded the stock to "neutral" from "buy" on a valuation basis, noting a 59 percent jump since March 19.
BlackRock - Citigroup has downgraded the investment firm's stock to "neutral" from "buy," saying much of the good news surrounding the company is already priced into the stock.