Check out which companies are making headlines after the bell Monday:
Jamba Juice - The beverage company lowered its fiscal year 2013 guidance for same-store sales and profit margins, citing bad weather in key markets and constraints on consumer spending. Shares dropped sharply in extended-hours trading.
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Talisman Energy - Billionaire investor Carl Icahn disclosed a 61 million share stake in the oil and gas exploration company, according to his Tweet, adding he "may have conversations" with the management regarding strategic alternatives and board seats. Shares spiked higher in extended-hours trading.
Generac - The backup power generation product manufacturer said it will acquire Baldor Electric's generator business, but financial details of the deal were not immediately disclosed. The acquisition is expected to close in the fourth quarter of 2013. Shares were flat in extended-hours trading.
Shutterfly - The photo-publishing site named Dan McCormick its new senior vice president and COO. McCormick was previously the general manager of the company. Shares were largely unchanged in extended-hours trading.
Seaspan - The containership operator announced a 5.7 million share offering and concurrent $125 million convertible note offering. Shares declined in extended-hours trading.
ServiceNow - The enterprise software company was initiated with a "neutral" rating at Janney Capital. Shares were unchanged in extended-hours trading.
Kythera - The biopharmaceutical company announced a $100 million secondary offering through JPMorgan and Bank of America. Shares tumbled in extended-hours trading.
Tower Group - The property and casualty insurance company said it has completed a comprehensive review of its loss reserves as of June 30, 2013. As a result, the company expects to strengthen loss reserves by nearly $365 million. Additionally, Tower expects to report a non-cash goodwill impairment charge of approximately $215 million for the second quarter of 2013. Shares slumped in extended-hours trading.
—By CNBC's JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)
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