A crisis of investor confidence has engulfed aspiring US gas exporter Liquefied Natural Gas Ltd., wiping more than 20 per cent from the value of the former market darling this week alone.

The worsening global energy price outlook and delays in signing up customers appear to have combined to erode the market's belief in the Perth-based company's ability to pull off its $US2.2 billion ($3 billion) Magnolia LNG project in Louisiana.