However, Cook needed $500 million more to keep the placing. Last year, the 77-year-old had $4.5 billion; this year he hit $5 billion.
Cook build his wealth through Cook Group, the Bloomington medical device maker, and has plowed millions of dollars into architectural passions in the southern Indiana town of French Lick.
The next-wealthiest Hoosier is Melvin Simon, No. 147 on the list. Simon saw his wealth slip by $100 million, to $2.8 billion, Forbes said.
Simon's younger brother, Herb, was No. 301, with $1.6 billion. That was up $100 million.
The Simons built their fortunes through Indianapolis-based Simon Property Group, the nation's largest shopping mall company.
The only other Hoosier on the list was Dean White, who generated his money through billboards and hotels. Listed as 281th, White was cited as having $1.7 billion, the same as last year.