Pacific Gas & Electric Co. (PG&E) employees work to fix downed power lines burned by wildfires in this aerial photograph taken above Santa Rosa, California, U.S., on Thursday, Oct. 12, 2017.

Check out the companies making headlines after the bell:

PG&E shares rose as much as 2 percent during the extended session Monday after the stock plummeted over 17 percent during the trading day. State regulators are investigating whether the utilities company's facilities were involved in the beginning of the California wildfires that have killed 31 people.

Eventbrite shares declined over 8 percent after hours as the company missed earnings expectations. The company reported a loss of $1.24 a share, while analysts predicted a loss of 47 cents per share. However, it beat revenue expectations, reporting $73.6 million. Analysts had expected $71.7 million. The company gave strong revenue guidance for the fourth quarter.

Sage Therapeutics dropped more than 2 percent during the extended session. The drop came after Leerink, an investment bank focused on health care, described the company as its least favorite in the biopharmaceutical space, giving the stock a price target of $80 -- well below Monday's closing price of $121.44. Leerink said Sage's drug for postpartum depression, Zulresso, is a niche product that will have low peak sales and a slow ramp after approval.

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