A sign for Tokyo Electric Power Co. (Tepco) is displayed outside the company's local sales office in Fukaya City, Saitama Prefecture, Japan, on Thursday, June 23, 2011. About 3 trillion yen ($37 billion) of Tokyo Electric's market value has been erased since the March 11 earthquake and tsunami knocked out the Fukushima Dai-Ichi plant and caused radiation to spew over more than 600 square kilometer