Who Owns UNIX? The Revived Legal Battle Over Unix Code

The article revisits the long‑standing legal controversy over who owns the UNIX code base, a dispute that has re‑emerged in a 2026 court hearing after more than two decades of litigation.

The conflict began in 1998 when IBM partnered with Santa Cruz Operation (SCO) – alongside Intel and Sequent – to create “Project Monterey,” a unified UNIX intended to run on multiple processor architectures.

By 2001 Project Monterey was close to delivery, achieved by merging source code from IBM’s and SCO’s UNIX variants.

Around the same time, the nascent Linux operating system appeared and demonstrated the ability to run on diverse CPUs. IBM, seeing Linux’s potential, withdrew from Project Monterey and allegedly contributed Monterey code, including parts of its AIX and Z operating systems, to the open‑source project. SCO claimed that it owned portions of that code and sued IBM.

SCO and its successors kept the lawsuit alive, hoping to secure ownership of parts of the Linux code base and IBM’s contributions, which could yield substantial financial gains.

The litigation series concluded in 2021 with a settlement: the parties agreed to end the dispute, while IBM denied any wrongdoing.

After the settlement, SCO sold its assets to a company called Xinuos, which continued the legal fight. Xinuos’s case proceeded quietly until a new milestone on June 22, 2026, when an online hearing was held; the presiding judge was even inadvertently muted during the session.

Both sides have revived arguments about Project Monterey, debating the relevance of earlier lawsuits, who owned which code and when, and whether the antiquated contractual language in the original agreements has expired, potentially closing the legal window.

The central question now is whether Xinuos has standing to pursue the claim or if the statutory limitations and old legal terms have rendered the case moot, suggesting the dispute may continue indefinitely.