New Delhi, Sept. 27 -- Meta Platforms Inc. is finally seeing the stock breakout that beleaguered bulls had been banking on.

The Facebook parent's shares had jumped 36% in September through Thursday's close following the release of its Muse personal AI assistant, which has risen quickly to the top of app charts and muffled concerns that heavy spending on AI won't pay off. The stock is on pace for its best month since July 2013 and within striking distance of joining an elite group of companies worth at least $2 trillion.

"Muse clearly validates its AI strategy and position, after a year and a half where the stock was basically flat because people didn't know if AI was going to be a net positive or a net negative," said Rob Biederman, co-...