Check out the companies making headlines in midday trading.

Harley-Davidson — Shares of the motorcycle maker jumped 4.7% after the company announced its electric motorcycle unit, Livewire, will go public through a merger with a special purpose acquisition company, or SPAC. The deal is valued at about $1.8 billion and will trade on the New York Stock Exchange under the ticker symbol "LVW."

Pfizer — Shares of the vaccine maker jumped rose 4.6% after a new Israeli study showed its Covid booster shot provides strong protection against severe illness from the omicron variant. Its partner BioNTech saw shares jump 7.9% on the news. Separately, the company announced it will acquire drug developer Arena Pharmaceuticals for $6.7 billion in cash. Arena's shares soared by 80.3%.

Meme stocks — Speculative stocks that were once popular with retail investors on Reddit slid as traders bailed from their risky positions. GameStop's shares cratered 13.9% in midday trading, while AMC Entertainment lost 15.3%. Bed Bath & Beyond fell 6.4%.

SVB Financial Group — Shares of the financial services company and parent of Silicon Valley Bank fell 4% after it announced it would acquire tech equity research firm MoffettNathanson to expand its investment banking capabilities.

Bristol-Myers Squibb — The biopharmaceutical company saw shares rise 4.7% after it announced a dividend increase of 10.2% over last year's quarterly rate, as well as an additional $15 billion share repurchase authorization.

Halliburton, Exxon Mobil — Shares of the energy companies fell after Iraq's energy minister said they're in talks over the potential sale of Exxon's stake in the West Qurna-1 oil field in southern Iraq, Bloomberg reported Monday. Halliburton's shares fell 5%, while Exxon's shares lost 2.1%.

Coca-Cola — Shares of the beverage company gained 2.6% after JPMorgan upgraded the stock to an overweight rating. The firm expects top-line momentum to build into 2022 driven by the ongoing economic reopening following the pandemic, and noted that the stock's current valuation is compelling both on a historical basis and relative to peers.

Rivian — EV maker Rivian's share got a 3.7% boost after MotorTrend names its R1T model the publication's 2022 truck of the year on Monday and called it "the most remarkable pickup truck we've ever driven." The R1T is the first mass-produced electric truck in the U.S., and the recognition is highly sought by automakers globally every year. Ford slipped 4.7%, and General Motors fell 6.4%.

Dollar Tree — Shares of the discount retailer fell less than 1% after activist investor Mantle Ridge announced efforts to try to replace the Dollar Tree board, which the company called "unwarrantedly aggressive." Dollar Tree also said it has offered to explore a settlement with Mantle Ridge, which owns 5.7% of the company.

Travel stocks — Stocks related to travel and the economic reopening were lower Monday amid continued fear and anxiety around the omicron Covid variant. United Airlines fell 5.2% while American Airlines fell more than 4.9%. Carnival and Royal Caribbean Cruises each dropped about 4%. Hotel chains Marriott and Hilton were 4% and 2.5% lower, respectively.

 — CNBC's Pippa Stevens contributed reporting