OMAHA - Warren Buffett's company says its third-quarter profit tripled as the improving economy and stock market boosted the value of Berkshire Hathaway's derivative contracts.

Berkshire said it generated US$3.2 billion ($4.4 billion), or US$2087 a share, in net income, up significantly from last year's US$1.1 billion, or US$682 a share.

Most of the swing in earnings is related to an unrealised US$1.7 billion gain on Berkshire's derivatives, some of which are tied to credit defaults and some to equity markets. That compares to a US$1.3 billion loss on Berkshire's derivatives in last year's third quarter.

Excluding the investment and derivative gains, its operating earnings were nearly flat at US$2.06 billion, or US$1325 a share. Last year, it reported operating earnings of US$2.07 billion, or US$1335 a share.

- AP