Alphabet Shares Sink 4% After Gemini 3.5 Pro AI Model Delayed

Alphabet shares sank 4% on Thursday after reports that the company delayed release of its Gemini 3.5 Pro artificial intelligence model, CNBC reported. The model is months behind schedule as Alphabet works to improve performance, particularly coding capabilities that fell short of internal expectations, according to Bloomberg.

Alphabet announced the model in May at its Google I/O developer conference and said then that it was in internal use with a broader rollout planned for the following month.

Meta last week released its Muse Spark 1.1 AI model, described by AI chief Alexandr Wang as the company's strongest for agentic and coding work. OpenAI released its GPT-5.6 Sol model last week, with CEO Sam Altman stating it is 54% more token efficient on agentic coding tasks.

An Alphabet spokesperson said the company is shipping quickly across a wide range of models while keeping them highly cost-effective for customers.

The spokesperson added that Alphabet is testing 3.5 Pro, an upgraded Flash model, and other models with partners and is productively engaged with the U.S. government. Shares of Alphabet slipped nearly 3% following the report, Reuters said.