Billionaire investor Warren Buffett’s Berkshire Hathaway said on Friday that its third-quarter profit fell as it lost money on a portfolio of stock index derivatives, despite strong market gains in the quarter.

Berkshire, whose interests range from insurance to railroads, posted a net profit of $2.99 billion or $1,814 per Class A share. A year earlier it earned $3.24 billion or $2,087 per share.

On an operating basis, excluding investment gains and losses, the company posted earnings of $1,692 per share, compared with $1325 a year ago. Analysts, on average, had expected earnings of $1,676.67 per class A share, according to Thomson Reuters I/B/E/S.

The company said operating earnings rose 36 percent in the quarter on contributions from railroad operator BNSF and a return to profitability at corporate jet service NetJets.