Check out the companies making headlines in midday trading.

Zoom Video – Shares dropped nearly 14% as investors digested signs that the video conferencing company's explosive growth this year may be slowing. Zoom's revenue grew 367% on an annualized basis during its fiscal third quarter, compared to a 355% growth rate in the previous quarter and 169% two quarters ago. The company reported earnings and quarterly guidance that topped analysts' expectations. The stock has surged more than 500% this year amid a pandemic boom.

Tesla – The electric vehicle company rose more than 2% after S&P Dow Jones Indices gave an update on how the company will be added to the S&P 500. After seeking advice from the investment community, the index provider said Tesla will be added to the benchmark all in one go, ahead of the opening bell on Dec. 21.

Kohl's — The retail stock surged more than 13% after Kohl's and Sephora announced that the beauty company will open more than 800 mini-shops inside the Kohl's stores by 2023. The move comes after rival retailer Target announced a similar partnership with Ulta Beauty last month.

Nikola – Shares of the embattled electric vehicle company slid more than 16%, building on Monday's 27% drop, following an update on Nikola's agreement with GM. The two companies announced a reworked and smaller agreement on Monday. GM will no longer take an equity stake in Nikola, and it also will not build the start-up's Badger vehicle. Nikola said it will refund previously submitted order deposits for the Badger.

Nio — The Chinese electric vehicle company slid 7% after Nio reported its latest delivery numbers. Nio said it delivered 5,921 vehicles in November, a monthly record for the company. The number is an increase of 109% compared with the same period last year, and an increase of more than 800 vehicles compared with October. The company also said it is accelerating the expansion of its production capacity to keep up with demand.

Charles Schwab — Shares of the e-broker popped more than 3% after Wells Fargo upgraded the stock to overweight from equal weight. The Wall Street firm said Schwab was an "excellent" play on the coronavirus "reflation" theme.

TripAdvisor — The travel stock rallied more than 5% after Bernstein initiated the stock with an outperform rating. While business activity has declined, the Wall Street firm sees opportunities for TripAdvisor to return to growth.

FedEx — Shares of the shipping company ticked nearly 2% higher after Barclays upgraded the stock to overweight from equal weight. The firm said it sees "growth opportunities" for FedEx amid an acceleration in e-commerce.

Moderna — Shares popped another 7% after a 20% gain in the previous session. The rally came after the drugmaker said Monday it will request emergency clearance from the Food and Drug Administration for its coronavirus vaccine with new data confirming it is more than 94% effective in preventing Covid-19. The stock also got a lift after Argus raised its price target on Moderna to $200 per share from $88 per share, the highest on Wall Street.

Pfizer — The drugmaker rose nearly 4% after announcing it, and its German partner BioNTech, have applied the European Medicines Agency for the conditional marketing authorization of their coronavirus vaccine.

Exxon Mobil — The stock rose more than 2% after the energy giant announced a more streamlined capital spending plan. The company also said it was going to write off up to $20 billion of assets.

— with reporting from CNBC's Jesse Pound, Yun Li and Pippa Stevens.