Traders work on the floor of the New York Stock Exchange (NYSE) ahead of the closing bell, November 30, 2017 in New York City.

Check out the companies making headlines midday Wednesday:

CVS Health — Shares of CVS Health plummeted 8.1 percent after the company issued lighter-than-expected guidance for 2019. CVS Health expects 2019 earnings to range between $6.68 and $6.88 per share, below an estimate of $7.41. The company also posted mixed results for the fourth quarter of 2018.

Southwest Airlines — Shares of Southwest Airlines slipped 5.65 percent after the company cut its revenue forecast by $60 million for its first-quarter, citing the U.S. government shutdown. The airline said the 35-day government shutdown stalled the launch of new jets and routes. Southwest also said the shutdown contributed to lower-than-expected passenger revenues.

Garmin — Shares of Garmin surged 17 percent after the maker of GPS devices posted adjusted quarterly earnings of $1.02 per share, 22 cents above estimates. Revenue also came in above Wall Street forecasts, with Garmin reporting strength in its fitness and outdoor product lines.

Walmart — Shares of Walmart fell 2.3 percent on Wednesday, giving back Tuesday's rally that was sparked by better-than-expected earnings and revenue for the holiday quarter.

Kandi Technologies Group —Shares of the Chinese electric auto maker surged more than 34 percent after receiving approval to import two of its models to the U.S. The stock's jump would be the biggest since June 10, 2013, when it surged 37.96 percent.

Charles Schwab — UBS downgraded Schwab's stock to sell, sending it down 1.3 percent. "The company has a strong customer franchise, but is facing headwinds to [balance sheet] growth from yield sensitive customers, an increasing regulatory burden, and limited rate upside," UBS says.

Transocean — Barclays upgraded the world's largest offshore driller to overweight, noting that "a transformed offshore industry is starting to emerge." The stock rose as much as 3.3 percent before closing 0.46 percent lower.

Magellan Health — Shares of the healthcare plan and pharmacy benefits manager surged more than 11 percent after Reuters reported that company is exploring a potential sale. The company has come under pressure from activist hedge fund Starboard Value to sell itself, and is in the early stages of considering acquisition interest, Reuters reported, citing people familiar with the matter.

Cadence Design Systems — Shares of the electronics design software maker surged more than 4 percent to a record high after reporting better-than-expected earnings and a 14 percent jump in revenue growth compared to last year. The company also raised its full-year forecast.

Devon Energy — Shares of the oil and natural gas giant rallied more than 6.5 percent after announcing it plans to spin off its Canadian assets from its core business. The Oklahoma City-based company also raised its quarterly dividend by a penny to 9 cents and increased its stock buyback program by $1 billion. The stock is on pace for its best day of trading since November 2016.

LaZBoy — The furniture maker jumped 11.4 percent after beating Wall Street's expectations for fiscal third-quarter sales and earnings. La-Z-Boys reported a 13 percent sales increase year over year.

IMAX — Shares of IMAX rose 2.6 percent after an analyst at MKM Partners suggested Sony might be "better off" acquiring the company than building out its own "premium large format" movie theater business. Neither company returned CNBC's request for comment.

—CNBC's Yun Li, Nadine El-Bawab, Kate Rooney, Michael Bloom and JR Reed contributed to this report.