Kenneth Griffin, Richest Man in Illinois, Endorses Marco Rubio

The billionaire hedge fund manager Kenneth C. Griffin is endorsing Senator Marco Rubio of Florida for president, adding another major Republican donor to Mr. Rubio’s roster.

“I’m really excited to be supporting Marco Rubio,” Mr. Griffin, who created the Chicago-based firm Citadel, told CNBC. “He will be the next president of the United States.”

His decision came weeks after another hedge fund executive, Paul Singer, endorsed Mr. Rubio, arguing that he is the best person to represent an optimistic and conservative message.

Mr. Griffin said that he let Mr. Rubio know of his decision on Wednesday morning.

“I have known Senator Rubio for a number of years,” Mr. Griffin said in a statement after the CNBC interview, “and he is an inspiring, courageous and bold leader who embodies the American dream of freedom and equal opportunity for all.”

He continued: “Senator Rubio is uniquely qualified to lead our nation with conviction and courage to tackle the pressing issues of our time, whether it’s strengthening our military, ensuring the safety of our people, or lifting the weight of government from our shoulders.”

Mr. Griffin, the wealthiest man in Illinois, was the driving force behind the successful effort to elect Bruce Rauner as governor and to put in place an agenda of overhauling the state pension system and reducing the impact of labor unions.

Mr. Griffin had debated among Mr. Rubio, Jeb Bush and Gov. Scott Walker of Wisconsin when considering who to support, and had donated to groups backing all three. Mr. Walker dropped out of the race several weeks ago.

The endorsement is a blow to Mr. Bush as Mr. Rubio tries to chip away at the one advantage the former Florida governor has — his substantial “super PAC” cash edge.