NEW YORK ( TheStreet) -- The release of Warren Buffett's annual letter to Berkshire Hathaway ( BRK.A) shareholders once again provided ample insight into the inner workings of the investor's vast empire and his views on a number of issues concerning the past, present and future of the company.

At 20 pages, the discussion was deep, detailed and riddled with his trademark humor. However, at the close of the missive, a number of issues remained untouched.

While some may gripe about the lack of insight into Buffett's feeling about his Goldman Sachs ( GS) investment or his mindset leading to his decision to dramatically cut his positions in oil majors ConocoPhillips ( COP) and Exxon Mobil ( XOM), perhaps the most pressing issue unaddressed in Buffett's tome was the company's plan of succession upon the financier's inevitable exit. He is 79 years old.

For years, one of the biggest questions on Wall Street has been who will be the leader of Berkshire Hathaway 2.0? Buffett, further aiding to the speculation, has insisted that the decision has already been made.

Unfortunately for curious individuals looking for specifics, the Oracle reportedly keeps the name of his heir apparent sealed in an envelope, stored in his Omaha, Neb. office.

With no hard clues from Buffett himself, investors have been left to speculate over who will take the reigns. Today, many predict that the daunting responsibility of penning the next chapter of Buffett's life's work will rest on none other than David Sokol.

For most of his tenure working under the Berkshire Hathaway umbrella, Sokol has led Berkshire Hathaway's utility branch, MidAmerican Energy Holdings. However, in the second half of 2009, Buffett added to his workload when he put him in charge of NetJets, the struggling subsidiary of Berkshire Hathaway, after the abrupt resignation of Richard Santulli, former CEO and founder of the jet-sharing company.

Thus far, Sokol's performance at this new post has been positive. Buffett praised his work in last week's shareholder letter, saying there has been a comforting decrease in the debt and that the firm is on the path to see a return to profit in 2010.

Sokol's work as the head of NetJets and MidAmerican are not the only examples of his business savvy. He, and Buffett's long time business partner Charlie Munger influenced Buffett to invest in BYD, the Chinese electric car company, a move that has reaped more than a billion dollars for the financier.

Sokol and Buffett also share a number of non-Berkshire related similarities. They both hail from Nebraska and as The Wall Street Journal pointed out, their early resumes include a number of parallels as well.

Despite being favored by a number of Buffett watchers, Sokol himself refuses to comment on the gossip. Questioned on the topic in a 2009 interview, Sokol insisted that there were a dozen or more executives working for Berkshire more qualified than he was. He went on to say that that type of speculation was a waste of time.

Upon his exit from Berkshire Hathaway, Buffett will leave behind a massive pair of shoes to fill. Though time will tell who will be chosen to take the reins, Sokol appears to be one of the most likely candidates for the job.

-- Written by Don Dion in Williamstown, Mass.
At the time of publication, Dion does not own any of the equities mentioned.

Don Dion is president and founder of Dion Money Management, a fee-based investment advisory firm to affluent individuals, families and nonprofit organizations, where he is responsible for setting investment policy, creating custom portfolios and overseeing the performance of client accounts. Founded in 1996 and based in Williamstown, Mass., Dion Money Management manages assets for clients in 49 states and 11 countries. Dion is a licensed attorney in Massachusetts and Maine and has more than 25 years' experience working in the financial markets, having founded and run two publicly traded companies before establishing Dion Money Management.

Dion also is publisher of the Fidelity Independent Adviser family of newsletters, which provides to a broad range of investors his commentary on the financial markets, with a specific emphasis on mutual funds and exchange-traded funds. With more than 100,000 subscribers in the U.S. and 29 other countries, Fidelity Independent Adviser publishes six monthly newsletters and three weekly newsletters. Its flagship publication, Fidelity Independent Adviser, has been published monthly for 11 years and reaches 40,000 subscribers.