After pouring $450 million into Florida real estate, Larry Ellison plans to lure the ultra-rich to an exclusive town just minutes from Mar-a-Lago

• Oracle cofounder Larry Ellison is helping raise the profile of the 400-resident island town of Manalapan, Fla. The multi-billionaire has already made a cumulative $450 million real estate investment in the town, and has taken over its biggest structure, the Eau Palm Beach Resort & Spa, which offers memberships to town property owners without initiation fees or dues.

Known for his tech feats as cofounder and chief technology officer of Oracle, in South Florida, Larry...