Meta has repeatedly pushed back the API launch of its latest AI model, Muse Spark, and is now testing the interface with partners ahead of a planned June 2026 release, a spokesperson said on Wednesday. The delay is adding to investor scrutiny over how Meta will turn its AI buildout into revenue, especially as the company plans $145 billion in 2026 capital expenditure. Concerns over that spending helped send the stock down more than 5% in April 2026 after costs came in higher than expected.