Billionaire Republican donor Maurice “Hank” Greenberg has made a $10 million donation to Right to Rise, the super PAC backing Jeb Bush’s presidential campaign, according to the Wall Street Journal. Greenberg did not deny making the donation, but declined to discuss it with the paper.

With the contribution, Greenberg, the former chairman and CEO of American International Group (AIG), joins the largest financial backers of the 2016 election cycle, who have largely chosen to support Republican rival Ted Cruz, according to the Hill. Those contributions include $15 million from the Wilks family fracking fortune, $11 million from hedge fund manager Robert Mercer and $10 million from private-equity fund founder Toby Neugebauer.

The massive donation from Greenberg came to the pro-Bush super PAC despite what is generally seen as a weak performance from the former Florida governor. According to RealClear Politics national averages, Bush currently sits in sixth place in the 2016 field with just 3.3 percent of respondents supporting the candidate. In early state voting, Bush does slightly better in Iowa, in fifth place with 4.8 percent, but stays in sixth place in New Hampshire with 8.3 percent.

In an October interview, Greenberg said he was supporting Bush and planned to donate to Right to Rise despite perceived weaknesses. “Does he have the flair others are looking for? No, but that's not what you judge a candidate on,” Greenberg told Bloomberg. “You judge him on his competence, and he got the job done in Florida.”

According to NBC News, Bush and his allies have spent $49 million in advertisements - $47.5 milion from Right to Rise and $1.5 million from his campaign - including $23 million in New Hampshire and another $10 million in Iowa. That $49 million represents more than a third of the $139 million total spent on ads in the entire 2016 race among all the candidates.

Bush and Greenberg have had a long-standing relationship, dating back to when Bush was the governor of Florida, noted Politico. When a series of hurricanes decimated large parts of Florida in 2004, Greenberg, who was then the chairman of an AIG foundation, wrote a $1 million check to help with relief efforts.