xAI is Elon Musk's artificial-intelligence company - founded in March 2023, merged with the X social platform in March 2025, acquired by SpaceX in a $250B all-stock deal on February 2, 2026, and rebranded SpaceXAI on July 6, 2026. It builds the Grok model family, whose latest release, Grok 4.6 (August 12, 2026), reuses Grok 4.5's foundation with improved fine-tuning for long-running agent tasks and coding, scoring 61 on the Artificial Analysis Intelligence Index to match OpenAI's GPT-5.6 Sol, plus Grok Imagine, an image-and-video generator Musk declared 'done' on July 5, 2026 and which topped the Image-to-Video Arena leaderboard; Grok features reached ~117 million monthly active users by March 2026, third in the US behind ChatGPT and Gemini. Its Memphis-area Colossus supercomputer complex - roughly 555,000 Nvidia GPUs expanding toward 2 GW and 1 million GPUs across a third facility, Colossus 3 ('MACROHARDRR' in Southaven, Mississippi) - has become a business in itself, leased to Anthropic ($1.25B/month for all of Colossus 1) and Google ($920M/month from October 2026), though its temporary gas turbines drew an April 2026 NAACP lawsuit; the Department of Justice moved in June 2026 to dismiss that suit on national-security grounds, and on July 31, 2026 SpaceX agreed with Mississippi regulators to fully remove the unpermitted turbines by July 2027. xAI also sued Minnesota over its new ban on AI 'nudification' tools, which took effect August 1 after a federal judge declined to block it. Grok is embedded in X (600M MAU), Tesla vehicles, and the Pentagon's GenAI.mil platform, now used by 1.5 million people daily across all its AI tools. The combined SpaceX went public on June 12, 2026 in history's largest IPO (~$85.7B raised) but has since fallen below its $135 IPO price and traded down more than 40% from its post-IPO high amid investor concern over xAI's compute spending (Q1 2026: $818M revenue against a $2.47B operating loss); its pending $60B Cursor (Anysphere) acquisition, facing expected antitrust scrutiny, is still targeted to close in Q3 2026; and the division's next act - the 6-trillion-parameter Grok 5 - is still training on Colossus 2 after slipping past two target windows, with no confirmed release date.