Check out which companies are making headlines after the bell Thursday:
Hertz Global - Shares rose after the travel solutions provider, known for its rent-a-car business, said it would add three activist investors, of Carl Icahn's choice, to its board. In return, the billionaire investor agreed not to wage a proxy fight against the company. Icahn has an 8 percent stake in the firm.
Ulta Salon - The stock rallied more than 10 percent after the cosmetics retailer easily beat second-quarter earnings estimates. The company also issued better-than-expected third-quarter revenue expectations.
Alliance Data Systems - The company said it will acquire digital marketing firm Conversant for $2.3 billion in cash and stock, or about $35 per share.
Conversant shares surged more than 22 percent, while ADS rose about 2 percent in after-hours trading.
HP - The firm announced it will acquire open sourced software provider Eucalyptus in an attempt to strengthen its cloud computing efforts. Shares edged lower in extended-hours trading.
Weibo - The China-based firm continued to move higher in extended trading, having ended the regular session up more than 13 percent, after T.H. Capital initiated coverage of the social media company with a "buy" rating.
—By CNBC's Karma Allen
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