Traders and financial professionals work ahead of the closing bell on the floor of the New York Stock Exchange.

Check out the companies making headlines midday Thursday:

HP Inc. — HP stock tumbled more than 17 percent after the computer and printer maker saw revenue miss estimates amid weakness in printer supply sales. HP said its market share and pricing for those supplies came under pressure during the quarter. Based on those results and the company's comments, Bank of America Merrill Lynch downgraded the stock by two notches, from "buy" to "underperform".

Box — Shares of the cloud company plummeted more than 18 percent on the back of disappointing revenue guidance. Box said it expects sales to range between $700 million and $704 million for fiscal 2020. Analysts polled by Refinitiv expected revenue guidance between $713.9 million and $749.9 million.

L Brands — Shares of L Brands fell more than 4 percent after the owner of Victoria's Secret and Bath & Body Works reported mixed results in the holiday quarter and announced plans to close 53 Victoria's Secret stores this year. Its earnings came in seven cents above estimates with adjusted quarterly profit of $2.14 per share, while the fashion retailer's revenue fell below forecasts on declining sales at its Victoria's Secret brand. It also issued weaker than expected full year guidance.

Booking Holdings — Shares of Booking Holdings slid nearly 11 percent after the company posted weaker-than-expected earnings in the last quarter. The operator of Priceline and other travel websites earned $22.49 per share for its latest quarter, compared to a consensus estimate of $19.42, according to Refinitiv. Its current quarter guidance was below consensus as well.

Celgene — Shares of biotechnology company Celgene sank more than 8 percent after two major Bristol-Myers Squibb shareholders announced their opposition to a deal between the two companies. Earlier this year, Bristol-Myers announced its intention to buy Celgene for $74 billion; that deal is now opposed by Starboard Value and top Bristol-Myers stakeholder, Wellington Management.

Monster Beverage — Monster Beverage surged more than 9 percent after posting better-than-expected earnings. The company reported fourth quarter earnings of 43 cents a share, above a FactSet estimate of 40 cents. Monster also authorized a $500 million buyback program.

Anheuser-Busch InBev — Shares of Anheuser-Busch InBev are up more than 4 percent after the world's largest brewer forecast strong revenue and profit growth in 2019 on higher prices and by consumers buying more of its premium beers.

Square — The electronic payments processor issued weaker-than-expected guidance for the first quarter of 2019, sending its stock down more than 2 percent. Square said it expects first-quarter earnings per share to range between 6 cents and 8 cents. Wall Street analysts expected profit guidance of 11 cents a share, according to Refinitiv.

—CNBC's Fred Imbert and Thomas Franck contributed to this report.