Lead: Two of the final co-founders at Elon Musk’s AI startup xAI, Manuel Kroiss and Ross Nordeen, have reportedly left the company as of late March 2026. Business Insider first reported Kroiss told colleagues he was departing, and later that Nordeen exited on Friday. The departures come as Musk says xAI is being rebuilt “from the foundations up” and after the company was folded under SpaceX’s corporate umbrella. The exits complete a wave that reduced the original co-founder group from 11 to none within weeks.
Key Takeaways
- Manuel Kroiss and Ross Nordeen have reportedly left xAI in late March 2026, according to Business Insider reporting.
- xAI began with 11 co-founders; with Kroiss and Nordeen gone, none of the original co-founders remain at the company.
- Kroiss led xAI’s pretraining team; Nordeen was described as Musk’s “right-hand operator” and arrived from Tesla.
- Elon Musk has said xAI “was not built right the first time” and that it is being rebuilt from the foundations up.
- xAI was recently acquired by SpaceX, bringing xAI, SpaceX, and X (formerly Twitter) under one umbrella while SpaceX explores a possible public listing.
- Nordeen was reportedly involved in planning large layoffs at Twitter after Musk’s 2022 acquisition, a background that preceded his xAI role.
Background
xAI launched with a high-profile founding team that totaled 11 co-founders, reflecting Musk’s intent to accelerate AI development outside conventional corporate structures. The startup attracted attention because of Musk’s public profile and because its stated goals intersect with both consumer-facing AI and infrastructure-level model research. Over recent months, news outlets tracked a steady attrition of early team members, a pattern that industry observers linked to organizational changes and shifting priorities.
In parallel, Musk announced that xAI would be integrated under SpaceX’s corporate umbrella, a move that folds xAI together with SpaceX and X (formerly Twitter) as SpaceX has weighed plans to go public. That consolidation has fueled speculation about how xAI’s research agenda and commercial strategy will change when aligned more closely with SpaceX’s broader engineering and financing goals. Stakeholders inside and outside the company have watched departures for signals about leadership direction and technical priorities.
Main Event
According to reporting by Business Insider, Manuel Kroiss told people this week that he was leaving xAI; the outlet later reported that Ross Nordeen departed on Friday. Kroiss had overseen xAI’s pretraining efforts, a central technical function responsible for the large-scale model training that underpins modern generative AI systems. Nordeen, who previously worked at Tesla, was described by sources as Musk’s close operational lieutenant and was said to have had a hand in planning workforce moves at Twitter following Musk’s 2022 acquisition.
The announced departures follow Musk’s own public assessment that xAI’s initial architecture and organization were flawed and that the company is being rebuilt from the ground up. Industry reporting suggests the exits are part of a broader reset that includes ownership changes and internal restructuring. TechCrunch reached out to xAI for comment but had not received a response at the time of publication.
Employees and former staff described a fast-moving environment in which strategic pivots, leadership changes, and corporate realignment under SpaceX accelerated decision timelines. While some departures were framed as voluntary, others occurred amid wider team reorganizations; sources interviewed by outlets familiar with the company noted both technical disagreements and managerial reshuffles as drivers.
Analysis & Implications
The exit of the final two co-founders removes a layer of original stewardship and institutional memory that can matter for continuity on long-term research projects. Pretraining teams curate datasets, manage compute allocations, and tune training regimes—roles Kroiss reportedly led—so his departure could slow or redirect ongoing model work until new leadership is in place. Rebuilding foundational systems, as Musk described, typically requires revalidating pipelines, retraining models, or rewriting core codebases, all activities that increase near-term operational risk.
Bringing xAI under SpaceX raises questions about resource allocation and strategic priorities. SpaceX’s engineering culture and financing model differ from a standalone AI lab: priorities may shift toward applications that align with SpaceX’s interests (e.g., autonomy, communications), or toward projects that present clearer paths to revenue. If SpaceX pursues a public offering, leadership could favor operational discipline and milestones that appeal to public markets over exploratory blue-sky research.
Externally, the departures may influence talent flows in the AI sector and how other startups approach founder retention during rapid restructuring. For partners and customers, repeated leadership turnover can complicate negotiations, contractual timelines, and product roadmaps. Regulators and investors watching Musk’s constellation of ventures will likely scrutinize how quickly xAI stabilizes and whether research outputs remain consistent with prior claims.
Comparison & Data
| Metric | Value |
|---|---|
| Original xAI co-founders | 11 |
| Co-founders remaining before March 2026 wave | 2 |
| Co-founders after Kroiss & Nordeen departures | 0 |
| Reported public remark about rebuild | “being rebuilt from the foundations up” (Musk) |
The table shows a full turnover of the initial co-founder group within months of intensive reorganization. Such complete turnover is notable: while tech startups often see founder changes, a shift from 11 original co-founders to none within a short span signals a deep structural reset. That reset coincides with ownership consolidation under SpaceX and public comments from Musk about fundamental rework.
Reactions & Quotes
“xAI was not built right the first time around; it is being rebuilt from the foundations up,”
Elon Musk (public statement)
The comment frames the departures as part of an acknowledged course correction rather than isolated personnel exits.
“Kroiss led pretraining work and Nordeen operated closely with Musk, and both have now left,”
Business Insider (reporting)
Business Insider’s reporting provided the immediate basis for public knowledge of the departures; TechCrunch sought comment but had not received one.
“When founding teams dissipate, the technical continuity for long-running model projects can be disrupted, at least temporarily,”
Independent AI researcher (expert commentary)
Experts note that loss of founding engineers can slow progress until new leaders reestablish priorities and operational practices.
Unconfirmed
- Whether Kroiss and Nordeen’s departures were voluntary resignations or the result of internal dismissal processes remains publicly unverified.
- The extent to which the SpaceX acquisition directly precipitated these exits is not independently confirmed.
- Specific internal disagreements about model architecture or governance that led to the changes have not been corroborated by primary documents.
Bottom Line
The reported exits of Manuel Kroiss and Ross Nordeen complete a rapid unraveling of xAI’s original co-founder cohort and mark a clear inflection point for the company. Musk’s public framing of a foundational rebuild and the transfer of xAI under SpaceX suggest the organization is entering a new phase that may prioritize different technical goals and governance norms.
For observers—investors, partners, researchers—the immediate focus will be on who replaces key technical leads, how quickly pretraining and model development work stabilizes, and whether the reorganization yields clearer milestones for commercialization or research outputs. Until those transitions are visible and communicated, uncertainty about xAI’s near-term roadmap will persist.
Sources
- TechCrunch — technology reporting on xAI departures (news outlet).
- Business Insider — reporting cited for departures of Manuel Kroiss and Ross Nordeen (news outlet).