Oracle Corp., the world's third-largest software maker, on Friday said Chief Executive Larry Ellison adopted a plan to sell up to 100 million of the company's shares over the next nine months.

Ellison also plans to gift almost 2 million shares to the Ellison Medical Foundation, which supports biomedical research.

Oracle said if Ellison completes all the sales and gifts detailed in the plan, he would own about 1.173 billion shares, or 22.7 percent, of Oracle's outstanding stock.

Based on their closing price of $20.61, the 100 million shares would be worth $2.06 billion. Earlier on Friday, Oracle's shares rose to their highest level in more than five years.

The Rule 10b5-1 trading plan adopted by Ellison allows corporate officers and directors to conduct prearranged stock trading if they don't have material, nonpublic information.

Forbes magazine ranked Ellison as the fourth-richest American in its annual list last September.