In May the Australian Energy Regulator determined default market offer prices would fall by up to 10% from July, with NSW and south-east Queensland households on standing plans seeing decreases between 3.4% and 10.7% and South Australians on flat rates a 1.4% increase. However, about 90% of households are on market offers where retailers are not obliged to pass on reductions, and some have raised fixed daily supply charges while lowering per-kilowatt-hour rates — a shift that can increase overall bills for low-usage customers. Energy Minister Chris Bowen has asked the AER and ACCC to investigate the practice.