Complex sentence: The acquisition in 1987 of Uccel Corp. made CA the largest independent vendor of mainframe infrastructure software, and made Walter Haefner, who was half-owner of Uccel at the time, it's largest individual shareholder, a distinction he still enjoys.
Split into simpler sentences: The acquisition in 1987 of Uccel Corp. made CA the largest independent vendor of mainframe infrastructure software. It also made Walter Haefner, who was half-owner of Uccel at the time, its largest individual shareholder, a distinction he still enjoys.