(Bloomberg) -- Here’s a theory from Charles Munger on why hisfriend Warren Buffett has been sosuccessful building Berkshire Hathaway Inc. into one of the world’smost valuable companies:

“He has a lot of time to think,” Munger told investors in LosAngeles on Feb. 10. “Warren is sitting on top of an empire now, andyou look at his schedule sometimes, and there’s a haircut.‘Tuesday: Haircut Day.”’

Buffett fans have cleared their own schedules this weekend. OnSaturday, Berkshire is set to release its annual report online. Asin years past, it will include a lengthy letter written by the85-year-old billionaire about the company, investing and whateverelse he’s been thinking about. Here are some themes to watch:

Succession

It’s the big unanswered question at Berkshire: Who will followBuffett as chief executive officer? Investors and the businesspress have speculated about the leading candidates for years. ButBuffett has avoided divulging any names. While it’s unlikelythat’ll change, there’s always a chance for a surprise.

There are some clues. In a letter last year, Buffett said theboard had settled on the right candidate and that, in somerespects, the person “will do a better job” than he’s doing. FutureCEOs, he added, should come from the company’s ranks and be“relatively young” so they can average at least 10 years at thehelm.

Munger, Berkshire’s vice chairman, dropped a bigger hint. In aseparate letter to investors last year, he highlighted theaccomplishments of two Berkshire managers: Ajit Jain and Greg Abel.Both men, Munger wrote, are examples of “world-leading” executiveswho are in some ways better than Buffett. Jain, 64, has runinsurance operations at Berkshire since the mid-1980s. Abel, 53, isin charge of the company’s energy unit.

Short of naming a successor, Buffett could explain more abouthow the company will be organized after he’s gone. Already, he’slined up some help for his successor. Todd Combs, 45, and TedWeschler, 54, Berkshire’s two investment managers, are poised totake responsibility for the company’s stock portfolio and advisethe next CEO on deals. Howard Buffett, the billionaire’s oldestson, will probably become non-executive chairman.

Stock portfolio

Buffett gained fame in the 1970s and 1980s as a stock picker.Using funds from Berkshire’s insurance subsidiaries, he made betson companies like the Washington Post Co. and Coca-Cola Co. thatsoared in value over the following decades.

Recently, he’s had a rough go in the market. Two of his biggestinvestments — International Business Machines Corp. andAmerican Express Co. — plunged over the last year as they’vestruggled to adapt to new technologies and competition. While AmExhas been a long-term winner for Berkshire, IBM trades for less thanwhat Buffett paid. Another big investment, Wal-Mart Stores Inc.,has also come under pressure.

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Buffett could use the letter to explain why he likes thecompanies’ long-term prospects. He could also remind investors thatBerkshire’s stock portfolio, while valued at more than $100billion, has become less important to Berkshire’s growth. Over thepast few decades, he’s built more value by acquiring dozens ofcompanies. Berkshire has interests in insurance, energy,manufacturing, media, retail and transportation.

Insurance earnings

Buffett has long said that Berkshire’s “core” business isinsurance. It owns Geico, the second-largest auto carrier in theU.S., and several other businesses that sell property andcasualty coverage.

Underwriting profit was down 43% at Berkshire’s insurance unitsthrough the first nine months of 2015 because of higher claimscosts. While Buffett has long said results from those businessescan be volatile, he’ll likely remind investors why insurance hasbeen good for Berkshire over the five decades he’s run thecompany.

Everything Else

Increasingly, Berkshire’s results are tied to a growing stableof businesses outside the insurance industry. Subsidiaries includewell-known consumer brands such as See’s Candies and T-shirt makerFruit of the Loom, as well as more-obscure operations like chemicalcompany Lubrizol and Israeli toolmaker Iscar. Berkshire also ownselectric utilities and BNSF, one of the largest U.S. railroads.

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Buffett always recaps how these operations fared and often givessome predictions about how they might perform in the year ahead.BNSF, for instance, spent heavily last year to improve service butis now facing a slump in commodity prices that’s hurting demand. Astronger dollar could also affect profit at Berkshire’ssubsidiaries that operate outside the U.S. Buffett may also weighin on what the plunge in oil prices means for his businesses.

Acquisitions

“Berkshire is now a sprawling conglomerate, constantly trying tosprawl further,” Buffett wrote in last year’s letter. He made goodon those words in 2015. In July, he joined with Jorge PauloLemann’s 3G Capital to finance H.J. Heinz’s tie-up with Kraft FoodsGroup Inc. A month later, Berkshire agreed to buy PrecisionCastparts Corp. for $37.2 billion.

Buffett is likely to give investors more details on why hebought Precision Castparts, which makes industrial components forthe aviation and energy industries. He said in August that the dealwould keep him from making another major purchase for about a year.Still, he could offer an update on his hunt for more acquisitionsand whether he’ll team up with 3G again.

Food for thought

Some of the most-discussed passages in Buffett’s letters havelittle to do with Berkshire. That’s because he often devotes asection to a business or investing topic that he finds interesting.Past reports have included thoughts on derivatives, stock optionsand public pension plans.

With China’s economy slowing, a U.S. presidential election infull swing, oil prices at their lowest levels in years, and centralbanks in Japan and Europe implementing negative interest ratepolicies, there’s no shortage of topics he could take on thisyear.

A blunder

Buffett is famous for his candor, and his letters often includesome sort of mea culpa. In 2015, he pointed out how he waited toolong to sell shares in Tesco Plc. The “thumb-sucking” costBerkshire, which posted a $444 million loss on the investment, hewrote. Expect the billionaire to call attention some new mistake inhis letter this year.

Related: Who will succeed Warren Buffett?

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