SINGAPORE (Oct 2): Two senior US-based energy executives have left commodity trader Noble Group in the past week, sources said on Thursday.

Brian Falik, the company's global head of energy capital since 2012, and Andrea Valerio, Stamford, Connecticut-based managing director of oil liquids, have both resigned, according to three people familiar with the matter.

Valerio had been with the company for over nine years and was responsible for trading oxygenates, including ethanol, MTBE and methanol.  

It was unclear why the executives left the company or what they would be doing next.  

Stephen Brown, a Noble spokesperson, said the company does not comment on personnel matters.

Noble has come under pressure from shareholders due to a fall in commodity prices and questions about its corporate accounting practices. Its shares have slumped nearly 75% since last summer.

Noble closed at 41 cents on Thursday.