After-hours buzz: GPRO, MDT, TWC & more

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Check out the companies making headlines after the bell Wednesday.

GoPro plunged as much as 28 percent in after-hours trading following a halt.The struggling wearable-camera maker trimmed its guidance and announced it would cut its workforce by about 7 percent. GoPro sees fourth-quarter and full-year 2015 sales of $435 million and $1.6 billion, respectively. Analysts had expected fourth-quarter revenue of $512 million, according to a consensus estimate from Thomson Reuters.

Shares of Medtronic ticked up in after-hours trading. The medical device maker recently said it planned to buy back shares worth up to $5 billion over the next couple of years. Medtronic also raised the lower end of its full-year adjusted earnings forecast range to $4.36 per share from $4.33, keeping the higher end unchanged at $4.40.

Time Warner Cable stock inched upward in extended trading. Last week, the media company announced that up to 320,000 customers may have had their email passwords stolen. The company said email and password details were likely gathered either through malware downloaded during phishing attacks or indirectly through data breaches of other companies that stored Time Warner Cable's customer information.

After a bad week for oil, shares of the Williams Companies rebounded slightly after the bell. Still, shares of the Oklahoma-based energy company are trading at a fraction of their 52-week high of $61.38 a share.

Extra Space Storage also rose in after-hours trading. The company will be replacing Chubb in the S&P 500 effective after the market close on Jan. 15.

.— Reuters and CNBC's Christine Wang and Jacob Pramuk contributed to this report.