NEW YORK (TheStreet) -- Last week, investors uncovered important clues as to the current state and future prospects for the Berkshire Hathaway (BRK.A) - Get Report stock portfolio.

The earnings performances of its top holdings

Coca-Cola

(KO) - Get Report

,

Wells Fargo

(WFC) - Get Report

and

American Express

(AXP) - Get Report

were decidedly mixed. This week, a handful of other notable firms in this legendary portfolio followed suit. Again, there proved to be both points of strength and hints of weakness.

On Wednesday,

ConocoPhillips

(COP) - Get Report

presented investors with its quarterly performance numbers and outlook. Despite seeing a dip in third-quarter earnings, the oil giant's profits were positive. High energy prices helped the firm blow past analyst expectations.

Exxon Mobil

(XOM) - Get Report

helped to keep the mood high when it reported standout earnings on Thursday morning.

Looking ahead, ConocoPhillips will likely be an exciting name to watch as it prepares to split its refining and production branches into two separate entities. The plan is projected to be completed next year. It will be interesting to see if

Warren Buffett

takes any action in response to this break-up.

Shares of COP currently represent a respectable slice of the Berkshire portfolio. However, on a number of occasions in recent memory, investors have watched the Oracle of Omaha pared back his exposure to the company. In the past, Buffett has admitted that his decision to sharply increase his exposure to COP in 2008 had been a mutli-billion dollar mistake.

Whereas rising commodity prices helped ensure strong earnings numbers for ConocoPhillips and other energy players over the past quarter, the same could not be said for

Procter & Gamble

(PG) - Get Report

, a Buffett staple. On Thursday, the consumer giant reported strong sales that fell in line with analyst expectations.

Any optimism was quickly dashed, however, when the firm presented an overcast outlook. Citing rising cost pressures, P&G slashed its outlook for the quarter ahead, as well as its full-year sales projections.

>>View Warren Buffett's Portfolio

Buffett-blessed companies in the U.S. saw mixed action this week. Meanwhile, investors learned of some promising news regarding one of the Nebraska native's more unusual foreign investments.

During the middle of the week, it was announced that BYD, the battery maker-turned-electric car manufacturer, had begun selling its e6 to Chinese customers. This all-electric crossover has had its share of delays; the vehicle was slated to be available for consumers in 2009.

According to reports from

Bloomberg

the car will be priced at 369,800 yuan ($58,200).

The e6 rollout is a welcomed bit of good news for the company. Still, it remains to be seen if the introduction of this new model can help the company turn itself around. Once wildly popular and highly praised as a leader within the alternative vehicle industry, BYD's shares have struggled as it has faced heavy pressure over the past few years as a result of weak profits and declining sales.

Chinese auto demand will continue to drive much of BYD's performance. However, increasingly, the company is taking steps to break into overseas markets as well. In addition to announcing the e6 rollout, the company opened the doors of its new Los Angeles headquarters this week. In the coming year, the firm is hoping to attract U.S. consumers and businesses with new models such as its e6 and an all-electric bus.

Written by Don Dion in Williamstown, Mass.

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At the time of publication, Dion Money Management did not own any equities mentioned.