Stocks making the biggest moves midday: Palantir Technologies, Summit Therapeutics, JetBlue Airways and more

Check retired the companies making headlines successful midday trading:

Palantir Technologies, Dell Technologies — Palantir and Dell jumped 14% and astir 4%, respectively, pursuing the announcement aft the doorbell Friday that some stocks would articulation the S&P 500 before the open connected Sept. 23. Palantir is acceptable to instrumentality American Airlines' spot, portion Dell is going to regenerate Etsy.

Summit Therapeutics — The biotech banal surged astir 56% aft the institution announced that its lung crab cause campaigner outperformed Merck's Keytruda successful signifier 3 objective trial. Merck shares dipped astir 2% pursuing the news.

JetBlue Airways — The hose banal popped astir 7% aft Bank of America expert Andrew Didora upgraded the steadfast to neutral from underperform. Didora said JetBlue's "self-help initiatives," specified arsenic gross betterment strategies, are opening to amusement aboriginal signs of impact. The expert doubled his terms people to $6, which would correspond a 13% upside from Friday's close. JetBlue last week hiked its third-quarter gross estimates.

Boeing — The craft maker's banal moved much than 3% higher aft the institution reached a deal with a mill workers union, perchance avoiding an costly strike. 

MarineMax — Shares popped much than 4% aft a Citi upgrade to bargain from neutral. The steadfast said the vessel trader should payment from the Federal Reserve cutting involvement rates.

Arm Holdings — The banal gained astir 7% aft the Financial Times, citing radical acquainted with the matter, reported that Apple volition usage Arm's next-generation spot plan successful the iPhone 16, which is acceptable to marque its debut connected Monday.

United States Steel — Shares added astir 5% connected a JPMorgan upgrade to overweight from neutral. The steadfast thinks the caller pullback presents a buying accidental and expects shares could retreat further if the company's planned sale to Nippon Steel falls through.

Cannabis stocks — Cannabis stocks moved higher aft erstwhile President Donald Trump said successful a Truth Social post that helium volition enactment legalizing big marijuana usage successful Florida. Shares of Tilray Brands precocious astir 5%, portion the AdvisorShares Pure US Cannabis ETF (MSOS) accrued much than 12% and the Amplify Alternative Harvest ETF (MJ) roseate much than 7%.

— CNBC's Alex Harring, Hakyung Kim, Yun Li, Jesse Pound and Michelle Fox contributed reporting.