Complex sentence: When Microsoft entered an agreement with IBM to develop OS/2, it lost interest in promoting Xenix; in 1987 Microsoft transferred ownership of Xenix to SCO in an agreement that left Microsoft owning 25% of SCO, which continued to market it.
Split into simpler sentences: When Microsoft entered an agreement with IBM to develop OS/2, it lost interest in promoting Xenix. In 1987 Microsoft transferred ownership of Xenix to SCO in an agreement that left Microsoft owning 25% of SCO, which continued to market it.