xAI Is Now SpaceXAI on the Nasdaq — and Grok 4.5 Tops the Legal AI Benchmark on Day One

Two things happened on July 6 and 8 that, taken together, mark a significant moment for Elon Musk's AI company: xAI officially rebranded to SpaceXAI, joined the Nasdaq-100 under the ticker SPCX, and simultaneously released Grok 4.5 — a 1.5 trillion-parameter Mixture-of-Experts model that landed at number one on Harvey's Legal Agent Benchmark on its first day of availability.

The rebrand formalizes what has been an open secret for months: xAI and SpaceX's operational infrastructure are deeply intertwined, from compute to distribution to the X platform serving as Grok's primary consumer surface. The SpaceXAI name makes that relationship explicit while positioning the company for institutional investors who want exposure to both space and AI under a single ticker.

Grok 4.5: what the benchmarks show

Grok 4.5 is a 1.5T-parameter Mixture-of-Experts architecture. Not all 1.5 trillion parameters run on every token — MoE models activate a subset of "experts" per forward pass, which keeps inference costs down while allowing the model to specialize across domains.

The headline number from launch-day evaluations: 83.3% on Terminal-Bench 2.1, a coding and tool-use benchmark that emphasizes multi-step agentic tasks over single-turn code completion. That's a competitive result in a field that's moved quickly since the summer of 2025.

The more commercially significant number is the score on Harvey's Legal Agent Benchmark — a legal-reasoning and document-analysis evaluation used by major law firms to vet AI tools before deployment. Grok 4.5 ranking first there is meaningful because legal is one of the few enterprise verticals where AI adoption has outrun the hype: firms are using these models in production workflows, not just pilots.

Pricing and availability

SpaceXAI set Grok 4.5's API pricing at $2 per million input tokens and $6 per million output tokens — positioning it below GPT-5.5 and Claude Opus 4.8 on price while claiming comparable or superior performance on the benchmarks it targets. The model is available via the xAI / SpaceXAI API as of July 8.

Consumer access through the X platform and Grok.com follows the standard tier structure: free users get limited queries, Premium subscribers get higher rate limits, and API access is pay-per-token with no subscription required.

What the rebrand means for competition

Joining the Nasdaq-100 as SPCX gives SpaceXAI index exposure — passive funds that track the index will hold the stock, which brings institutional buying pressure independent of individual investor sentiment. That's a meaningful structural change in who owns the company and how it's valued.

For the AI industry more broadly, the rebrand underlines how much the competitive landscape has shifted from pure research organizations to vertically integrated conglomerates: SpaceXAI has rockets, a social platform, a hardware manufacturing pipeline (Tesla's AI chip ambitions), and now a flagship model that's competitive with the best from OpenAI and Anthropic. That combination of distribution leverage and model capability is something neither OpenAI nor Anthropic can fully replicate in the short term.

Whether Grok 4.5's legal benchmark lead translates into real enterprise adoption — and whether SpaceXAI can hold that lead as competitors update — will be clear within the next model generation cycle.

Sources: ThursdAI July 2026 releases; LLM Stats.