Warren Buffett’s Berkshire Hathaway has acquired a stake in Chubb worth $US6.7 billion ($10 billion) at the end of March, a filing to the US Securities and Exchange Commission shows.

The Nebraska-based company held 25.9 million shares in Chubb at the end of the first quarter, which would give it a stake of about 6% based on 406 million shares outstanding. 

The disclosure last week caused trading in Chubb to surge, with the share price closing up 4.7% at $US264.88 ($396) on Thursday. It ended the week at $US274.28 ($410). 

Berkshire Hathaway’s own insurance businesses include motor division Geico, Berkshire Hathaway Specialty Insurance and reinsurance. In other sectors, major operations encompass freight rail and a group of utilities and energy businesses. 

The company holds stock in a diverse range of US corporates, such as Apple, American Express, Coca-Cola, Kraft Heinz, Occidental Petroleum and global broker Aon, and it has “passive and long-term” interests in Japanese companies Itochu, Marubeni, Mitsubishi, Mitsui and Sumitomo. 

Berkshire Hathaway has not commented on its Chubb investment, which it started accumulating last year, according to media in the US. 

“Our goal at Berkshire is simple: we want to own either all or a portion of businesses that enjoy good economics that are fundamental and enduring,” Mr Buffett said in the most recent annual report. 

Chubb has operations in 54 countries and reported gross written premium of $US57.5 billion ($86 billion) last year. 

Insurer Ace, led by Evan Greenberg, acquired the company in 2015, retaining the Chubb name for the combined group. Mr Greenberg, who remains CEO, is the son of former AIG head Maurice “Hank” Greenberg.