Berkshire Hathaway (NYSE:BRK-A)(NYSE:BRK-B) isn't your average publicly traded company. With stakes in everything from candy to rail cars, it's easy to lose sight of which businesses really matter and which are mere rounding errors in its quarterly earnings reports.

Here's what shareholders should be watching closely when the company reports earnings on August 3. 

1. Can the insurers stay on track?

Last year was unusual for Berkshire, given its insurance units suffered a rare underwriting loss as a result of major hurricane and earthquake losses. Some of those losses were reversed in the first quarter when Berkshire reduced previous loss estimates, helping it show a large underwriting gain. Such gains are unlikely to boost underwriting performance this quarter.

Warren Buffett

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GEICO, a growth machine for Berkshire Hathaway, has benefited from certain pricing actions and growth in the number of policies in force. In the first quarter, the company reported that premiums per policy increased 8.2%, while the number of auto policies increased by 6.5%, resulting in a 15.6% increase in premiums earned.

Likewise, Berkshire Hathaway Primary Group, a collection of smaller insurance companies that underwrite commercial insurance, together reported a 14% increase in premiums earned in the first quarter. BH Primary Group is growing off a small base, but its underwriting record is undoubtedly the best in the insurance group. 

Reinsurance is unlikely to be a major generator of underwriting profit or premium growth, however, as even Warren Buffett has said that increased competition has made the business more difficult than in the past. That said, the reinsurance companies remain an important source of long-term and low-cost float that Buffett can invest as he sees fit.

2. Buffett's odds and ends

The manufacturing, service, and retailing segment includes an assortment of operating businesses that range from high-margin, billion-dollar rainmakers, like Precision Castparts, down to marginal businesses that include local newspapers in small U.S. markets.

The needle movers in the segment are well known by Berkshire investors -- Precision Castparts, IMC, Marmon, and Lubrizol -- businesses that together make up the majority of the highly profitable industrial manufacturers. Recent strength in the U.S. dollar could be a drag on Lubrizol, which, in the first quarter, benefited from a general decline in the dollar because it derives a significant portion of revenue overseas.

The industrial businesses generate about one-fourth of combined manufacturing, service, and retail revenue, but because of their outsized margins, they produce more than half the combined segment's pre-tax profits. Notably, because the segment produces the majority of its profit in the United States, it's a natural beneficiary of a lower corporate tax rate in 2018.

3. A rosy outlook for BNSF Railway

Rising commodity prices have been a boon for railroads, helping drive higher carload volumes across the industry. BNSF disclosed in its carload report that total carloads increased 5.8% in the second quarter compared to the year-ago period. Intermodal volumes increased by 4.9% year over year in the second quarter.

Though revenue per carload remains a question mark, a healthy single-digit increase in volume bodes well for BNSF's earnings this quarter. Already, competitors CSX Corporation and Union Pacific reported earnings that topped analysts' consensus estimates for the quarter.

4. No surprises for the power plants

Berkshire's utility and energy businesses are almost a royalty on energy consumption, given they make money producing power in markets where they have a monopoly on energy generation and distribution. Approximately 88% of its energy-related revenue was derived from regulated markets in the most recent quarter.

Regulated utility businesses are as steady as it gets and remain one of Berkshire's favorite places to deploy excess cash, one project at a time. Its NV Energy subsidiary recently agreed to acquire projects that together produce about a gigawatt of solar power, while MidAmerican Energy has plans to develop a $922 million wind farm in Iowa. Though utilities and energy investments will never be a home run, they offer the opportunity to earn reliable returns on large sums of cash.

5. Buybacks

In the past, Berkshire Hathaway had a policy to buy back stock at any price below 1.2 times book value. That changed in July, when Berkshire said that it was removing the valuation threshold for repurchases, replacing it with a policy to repurchase stock when both Buffett and Charlie Munger "believe that the repurchase price is below Berkshire's intrinsic value, conservatively determined."

After Berkshire reports earnings, its new policy will go into effect, as the company said it wouldn't pursue any share repurchases until it reported second-quarter results.

Berkshire Hathaway has struggled with the high-class problem of having more cash than investment ideas. With roughly $108 billion of cash on hand at the end of the first quarter, Berkshire is looking high and low for places to put money to work.

It's invested heavily in airlines, put more than $40 billion to work buying shares of Apple, and reportedly even explored a convertible debt investment in the ridesharing company, Uber Technologies, all of which are investments that Berkshire has traditionally shunned.

A relaxed share repurchase program may tempt Buffett and Munger to start buying stock in the business they know best: Berkshire Hathaway.

Jordan Wathen has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Apple. The Motley Fool has the following options: long January 2020 $150 calls on Apple and short January 2020 $155 calls on Apple. The Motley Fool recommends Berkshire Hathaway (B shares). The Motley Fool has a disclosure policy.