Google’s Gemini 3.5 Pro delayed as model falls short

Alphabet's ↗ 4.44% Google is months behind schedule on delivering Gemini 3.5 Pro, its most powerful flagship AI model, as the technology has fallen short of the company's internal expectations, according to a Bloomberg report published Thursday.bloomberg

The delay has frustrated Google engineers, AI researchers, and managers, with many concerned that the company risks losing ground to rivals Anthropic and OpenAI, which have produced models that exceed Gemini's current capabilities.investing

Coding Performance at the Core of the Setback

The delay is driven primarily by efforts to improve the model's coding abilities, according to people familiar with the matter cited by Bloomberg. Both OpenAI and Meta Platforms ↗ 6.02% recently released new models that outpace Google's current offerings in AI for writing code. Late last month, Google updated the data being used to train Gemini to improve these skills, but the results were disappointing, the report said.investing+1

Alphabet shares fell following the report on Thursday.investing

A Pattern of Slipped Timelines

Google first announced Gemini 3.5 Pro at its I/O developer conference on May 19, 2026, alongside the release of Gemini 3.5 Flash. CEO Sundar Pichai told the audience the Pro model would arrive "next month," drawing groans when he acknowledged it was not yet ready. June came and went without a broad release, and Business Insider reported in late June that Google had pushed the launch into July to gather feedback from early testers.investing+4

The model has remained in limited enterprise preview on Vertex AI, with the general developer community still waiting. Reports in mid-July indicated that multiple tested checkpoints had failed to reach the performance bar Google set internally, particularly when measured against competitors like OpenAI's GPT-5.6.windowsforum+2

Structural Challenges and Government Talks

Bloomberg's report noted that Google's organizational structure — with multiple layers of stakeholders involved in preparing models for release and integrating AI across products including Search, Maps, and YouTube — can itself cause delays. Google has also been in discussions with the U.S. government, which has increasingly monitored the most advanced AI models, about capabilities and industry safety standards.investing

A Google spokesperson said the company is "shipping quickly across a wide range of models while keeping them cost-effective for customers," adding that Google is currently testing 3.5 Pro and an upgraded Flash model with partners.investing