Travis Kalanick, CEO of UBER

Bonnie Kalanick, the mother of Uber CEO Travis Kalanick, died on Friday evening as a result of injuries sustained in a boating accident near the waters of Fresno, California.

A letter distributed to Uber employees on Saturday stated that both of Kalanick's parents were sailing on Friday evening when disaster struck. Uber did not disclose the circumstances behind the accident, but called it an "unthinkable tragedy."