Giant US investment company Berkshire Hathaway has tripled its third-quarter profit to $US3.2 billion ($3.5 billion) due to lower insurance costs and higher revenue from financial products.

The company owns reinsurer Gen Re and insurers Geico and National Indemnity.

Its net profit soared from the $US1.06 billion ($1.2 billion) the Warren Buffett-chaired conglomerate earned last year, when derivative losses burned a significant hole in its accounts.

Insurance premium revenue increased 2% to $US6.6 billion ($7.2 billion) as net profit from reinsurance and insurance climbed to $US363 million ($394 million) against $US81 million ($88 million) in the third quarter last year.

Investment income also increased 21% to $US976 million ($1.06 billion).