Microsoft co-founder Paul Allen, who is rated by Forbes magazine as the world’s 37th richest person, plans to give away most of his $13.5 billion fortune.

In the statement, Allen said his estate would support causes including not-for-profit scientific research such as the Allen Institute for Brain Science.

His declaration came a month after Gates and fellow billionaire Warren Buffett launched a campaign dubbed the “giving pledge” that urges America’s richest individuals to commit half of their fortunes to charitable causes.

Allen co-founded Microsoft with Bill Gates in 1975. He left the company in 1983 and became an investor in a range of industries including media and cable

Allen also owns one of the largest private yachts in the world, a vessel named Octopus, which is often moored in Monte Carlo.