After-hours buzz: Petrobras, Outerwall, SunEdison and more

Traders work on the floor of the New York Stock Exchange.
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Traders work on the floor of the New York Stock Exchange.

Check out the companies making headlines after the bell Monday:

Outerwall, the company that owns Redbox video rental, said it would begin exploring 'strategic and financial alternatives,' which could mean either a break up or outright sale. The company has retained Morgan Stanley as a financial adviser. In extended hours, the stock soared by up to 15 percent.

Brazil's state oil company Petrobras saw shares slide in extended trading, as swelling protests call for the president's removal. Half a million protesters have hit the streets of Sao Paulo, Reuters reports, as a judge holds his ground on allegations of political kick-backs and bribes within the energy firm.

SunEdison shares edged higher after hours as Wall Street digests the solar energy company's terminated merger with Vivint Solar. Vivint hit a new 52-week low during the regular trading session Monday, after the two companies nixed the $2.2. billion deal last week.

Shares of equipment manufacturer Dover Corp. slid after the company said its oil- and gas- related markets have weakened, pushing their first-quarter financial results below prior expectations. The company also makes food and refrigeration equipment, sales of which remained solid, the company said in a release.

Among smaller stocks, shares of Weight Watchers dipped in light trading, paring gains after a pop late last week. Celebrity spokeswoman Oprah Winfrey unveiled a slimmer figure on her namesake magazine last week, attributing the change to her Weight Watchers regimen.

— CNBC's Christine Wang contributed to this report.