Ajit Jain is the head of Berkshire Hathaway's (NYSE:BRKA) (NYSE:BRKB) largest insurance business, Berkshire Hathaway Reinsurance Group. He is also widely considered to be a leading candidate to one day replace Warren Buffett as chief executive of the entire Berkshire conglomerate. While Jain's estimated $2 billion net worth pales in comparison to Buffett's, the executive does manage an insurance business with over $44 billion in float, considered by many to be the crown jewel of the Berkshire empire.

Will Jain one day take the reins from Buffett? Let's weigh the odds.

Warren Buffett

Warren Buffett. Image source: The Motley Fool.

What Berkshire Hathaway's current chief executive thinks of Ajit Jain

Over the years, both Buffett and his number two, vice chairman Charlie Munger, have each gone out of their way to applaud Jain as a highly effective leader, cunning strategist, and major driver of Berkshire profits. In 1999, for example, Buffett said,

"In Ajit, we have an underwriter equipped with the intelligence to properly rate most risks; the realism to forget about those he can't evaluate; the courage to write huge policies when the premium is appropriate; and the discipline to reject even the smallest risk when the premium is inadequate. It is rare to find a person possessing any one of these talents. For one person to have them all is remarkable."

Jain came up again in the 2010 letter to shareholders. Buffett said that "If [Munger], I, and Ajit are ever in a sinking boat and you can only save one of us, swim to Ajit." That's a strong testament to Jain's significance at the company.

In the 2015 letter it was Munger's turn, telling investors that Jain and the head of Berkshire's energy division, Greg Abel, are "proven performers who would probably be under-described as 'world-class.'"

Jain's good work has been rewarded over time, most recently with a promotion to head both Berkshire Hathaway Reinsurance Group and now Gen Re as well. The promotion came earlier this year when Tad Montross, the current CEO of Gen Re, announced his retirement. Montross had previously reported directly to Buffett; however, his replacement -- who has yet to be announced -- will report to Jain going forward. Gen Re had a float of $18 billion as of December 31, increasing the total float under Jain's management 41%.

Ajit Jain as Berkshire Hathaway CEO is possible, but no sure thing

As qualified as Ajit Jain is to take the helm of Berkshire, it's far from clear if he will actually become CEO one day.

First, Jain is 64, which would put him above the average age of CEOs of companies on the S&P 500. Buffett, who will turn 86 in August, is himself among the oldest CEOs on the list. However, Buffett was a spry 26 when he founded the first partnership that would ultimately become today's Berkshire Hathaway. Buffett has said in the past that the company hopes to promote someone who can lead the company for ten years or more. At 64, that's a plausible expectation for Jain, albeit not ideal.

Second, Jain is not the only qualified candidate in the mix for the job. His biggest competitor is likely the previously mentioned Greg Abel, who runs Berkshire's expansive energy business. Some speculate that Jain is simply too valuable to the company at the top of the insurance business and that Abel would be the better fit as a "capital allocator in chief," responsible for managing the company's sprawling balance sheet, mitigating risk, and delegating responsibility to the company's other world-class managers. And don't count out Todd Combs or Todd Weschler -- the duo gradually taking over investment decisions from Buffett and Munger -- as possible candidates as well.

Lastly, on multiple occasions Jain himself has publicly stated that he doesn't want the CEO job. Of course, it's one thing to say that publicly and with no job offer in hand, and a whole other thing to turn down an actual offer to be the chief executive of the number four company on the Fortune 500.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.