Stocks making the biggest moves midday: DraftKings, Sage Therapeutics, Vroom and more
New England Patriots cornerback Stephon Gilmore, #24, stretches during the New England Patriots practice session in Foxborough, Massachusetts, on Oct. 22, 2020.

Sage Therapeutics — Shares of the drug maker fell about 19% after the release of study results for its experimental depression drug. The treatment resulted in a statistically significant improvement in symptoms, although it could take up to six weeks to be effective.

Vroom — The used-vehicle e-commerce platform provider's shares fell more than 11% after it announced a convertible note offering of $500 million in convertible senior notes due 2026. Vroom plans to use the proceeds to invest in new technologies and other corporate purposes.

Novavax — Shares of Novavax fell nearly 10% despite the biotech firm's announcement Monday that its Covid-19 vaccine is safe and 90.4% effective. The company also said its vaccine remains effective when co-administered with the flu shot.

Ping Identity — The identity management solutions company saw its shares fall almost 8% after announcing it would offer 6 million shares of common stock by investment funds affiliated with Vista Equity Partners. Ping said it will not receive any proceeds from the sale but will bear the costs associated with it.

DraftKings — The sports betting company shed more than 4% after Hindenburg Research revealed that it had a short position against the stock. Hindenburg's report highlighted DraftKing's valuation as a concern and alleged involvement in questionable gambling activity by SBTech, which DraftKings merged with in 2020. DraftKings said in a statement that it was comfortable with SBTech's business history.

Fastenal — Shares of the maker of industrial and constructions supplies dropped more than 2% following a downgrade at Morgan Stanley. The bank slashed its rating on Fastenal to underweight from equal weight, saying the stock had limited upside due to a high valuation and execution risk as it continues the transition.

MicroStrategy — MicroStrategy's shares rose 5.3% after it said late Monday it plans to plans to sell up to $1 billion in stock to buy more bitcoin. The business software company currently owns more than 92,000 bitcoins. Bitcoin's price is also recovering this week from its price declines of the last month.

Exxon Mobil — Shares of the oil giant advanced 3.6% on the heels of an uptick in the price of oil, and after Bank of America reiterated its buy rating on the stock. The firm believes Exxon will raise its dividend before the end of the year, and sees shares jumping 45% from their Monday closing price to $90.

— CNBC's Maggie Fitzgerald, Hannah Miao, Jesse Pound, Yun Li and Pippa Stevens contributed reporting