Warren Buffett's Berkshire Hathaway Inc. BRK.A-N posted its first quarterly loss since 2001, hurt by losses on derivative contracts and a big investment in ConocoPhillips. The net loss for the insurance and investment company was $1.53-billion (U.S.), or $990 per class A share, and compared with a profit of $940-million, or $607, a year earlier. Excluding investments, operating profit fell 12 per cent to $1.71-billion, or $1,100 per share, from $1.93 billion, or $1,247. That profit was in line with the $1.7-billion that Mr. Buffett estimated at Berkshire's annual meeting last Saturday. Revenue fell 9.5 per cent to $22.78-billion. Results reflected $2.01-billion of writedowns on investments, including $1.9-billion tied to ConocoPhillips. BRK.B (NYSE) rose $80 to $3,132. BRK.A (NYSE) rose $905 to $95,295.