Berkshire Hathaway reported a nearly 30% decline in fourth-quarter operating profit, with insurance underwriting emerging as the primary drag on results. The company's insurance underwriting earnings more than halved to $1.56 billion, while insurance investment income dropped nearly 25% to $3.07 billion.

Warren Buffett's final quarter as CEO saw the conglomerate record $4.5 billion in impairment charges tied to its investments in Apple and HP. Operating earnings fell to $10.2 billion for the quarter ended December 31, compared with nearly $14.53 billion a year earlier. Net earnings per average equivalent Class A share declined slightly to $13,349 from $13,695.

The results matter because Berkshire Hathaway's diverse portfolio spanning insurance, railroads, energy, and manufacturing provides investors with a broad view of U.S. economic performance. The significant drop in insurance underwriting profits suggests potential challenges in the property and casualty insurance sector.