Tech Investor David Roux Sells Kailua-Kona, Hawaii, Estate for $37 Million It was the state’s highest residential sale so far in 2020 By Fang Block | Save Tech investor David Roux has sold his home in Kailua-Kona on Hawaii's Big Island for $37 million. Google Maps, Getty Images Tech investor David Roux has sold his home in Kailua-Kona on Hawaii's Big Island for $37 million. Google Maps, Getty Images A house in Kailua-Kona on Hawaii’s Big Island that belonged to tech investor and philanthropist David Roux sold for $37 million this week, making it the state’s most expensive residential sale this year, public records show.