Jonathan Raa / NurPhoto via Getty Images Palantir shares sank even though the AI software company posted record quarterly results that blew past analysts' estimates and raised its full-year revenue outlook for the third straight quarter Key Takeaways Major U.S. equities indexes were lower at midday Tuesday, with Palantir Technologies leading tech stocks lower. Palantir's stock sank amid some worries that it's overvalued, even though the AI software company posted better-than-expected quarterly results. ...

Sarepta's stock sank after studies of Duchenne muscular dystrophy treatments failed their primary endpoints. ...