Tesla and Larry Ellison have confirmed via a new SEC filing that Ellison owns 3 million shares, which are worth about $1 billion. The filing was necessary because Ellison agreed last week to join Tesla's board. Tesla did not say when Ellison bought the shares, except that it was earlier this year. However Ellison disclosed he had made a sizable investment back in October, the month when Tesla dropped near 52-week lows.