Check out the companies making headlines in midday trading. 

Boeing — Shares popped more than 3% after Patrick Ky, the head of Europe's aviation regulator, said the company's beleaguered 737 Max jet is safe to fly again. He added the aircraft could fly in the region once again before year-end.

Caterpillar — The farming equipment maker rose 3% after Wells Fargo upgraded Caterpillar to overweight from equal weight. Wells said it believes revenue growth will begin to accelerate in key markets in 2021.

Costco — Shares of the big box retailer popped 1.3% after Jefferies upgraded Costco to buy from hold. The firm said Costco is the "dominant" leader in the club warehouse sector and that its "digital underdevelopment" offers upside.

Navistar International — The truckmaker's stock surged 21% after CNBC's David Faber reported that Volkswagen's Traton unit was in talks to buy the rest of Navistar. The companies are very close to a deal at $44.50 per share, according to people close to the negotiations.

CIT Group – Shares of the bank jumped more than 22% after the company announced that it will merge with First Citizens in an all-stock deal. The combined company will be the 19th largest U.S. bank as measured by assets. Shares of First Citizens were up about 8% following the announcement.

Chewy – Shares of Chewy climbed nearly 4% after Jefferies upgraded the online pet retailer to buy from hold. The Wall Street firm's recent survey suggested that 37% of pet owners cited Chewy as their top e-commerce platform for pet food and supplies. Jefferies also said Chewy's "moat" is "more defensible than previously perceived."

Bank of New York Mellon – The stock gained more than 2% following the bank's better-than-expected quarterly results. The bank reported earnings of 98 cents per share, 4 cents above Refinitiv estimate. Its revenue also came in above Wall Street forecasts. 

Pfizer — Shares of the drugmaker rose 2.4% after CEO Albert Bourla said the company could know whether its Covid-19 vaccine candidate is effective by the end of the month, allowing it to apply for emergency use authorization in late November. The company is developing the vaccine with BioNTech, whose shares rose 2.1%.

Wynn Resorts — Shares of Wynn Resorts fell nearly 2% after Jefferies downgraded the casino and resort company to hold from buy. The bank said Wynn's leverage will remain "pressured" through 2022.

— CNBC's Maggie Fitzgerald, Jesse Pound, Pippa Stevens and Fred Imbert contributed reporting.

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