X avier Rubiralta is a Spanish billionaire who, along with his brother Marc, owns and runs Werfen, a global leader in the specialized field of in-vitro diagnostics. The privately held company was founded by their father, José María Rubiralta, in 1966. The family has built the company into a dominant player in niche but critical areas of hospital diagnostics. Werfen is particularly strong in the fields of hemostasis (diagnosing blood clotting disorders), critical care diagnostics, and autoimmunity.

While his brother Marc serves as the CEO, Xavier is the chairman of the board, and together they guide the strategy of the global enterprise. They have continued to expand the family business through organic growth and strategic acquisitions, solidifying their position as major, albeit low-profile, figures in the global medical device industry. Their shared ownership of the highly successful and privately held company is the source of their multi-billion dollar fortunes.