The cuts at the unit of Koch Industries Inc, the industrial conglomerate of billionaire conservatives Charles and David Koch, affected traders and support staff in its United States, Switzerland, United Kingdom and Singapore offices.

The positions involved were primarily in refined products and fuel oil trading and operations, according to the sources.

Some commodity trading firms and banks posted major losses last year due to muted client activity and wild fluctuations across energy markets. Bonuses across the industry were also low, and some hedge funds have chosen to exit energy trading.

Koch "made adjustments to its global commodity trading presence to better reflect the current market opportunities," said spokesman Rob Carlton, adding it would retain an active presence in commodity markets globally.

He declined to comment and the scope of the layoffs.

Sources said at least 10 traders globally had been let go at Koch as the company seeks to optimise under-performing units.

On Monday, trader AOT Energy separately said it had reduced some staff, including parting ways with its senior management team in Houston, and earlier this year pared its European distillates and U.S. Gulf Coast fuel oil business due to shrinking margins.

Several key commodities traders left Goldman Sachs Group Inc earlier this year, sources said, as the Wall Street firm seeks to turn around its struggling commodities unit.

Commodity-focused hedge funds including Andy Hall's Astenbeck Capital Management and Texas tycoon T. Boone Pickens' BP Capital have shuttered some operations in recent months.

(Reporting by Catherine Ngai and Devika Krishna Kumar in New York and Liz Hampton in Houston; Editing by Tom Brown)