After receiving the largest financial gift in its history, Palm Beach Atlantic University announced an ambitious plan to expand its business school — and take advantage of the recent surge in local hiring demands. For the project, longtime financial backers John J. and Sheila Rinker and the Marshall and Vera Lea Rinker Foundation have donated a total of $26 million to the private Christian university. The university's president, Debra A. Schwinn, said the Rinker Family's donation kicked off a $75 million funding campaign to build a six-story, standalone Marshall and Vera Lea Rinker Business building at its downtown waterfront West Palm Beach campus.