JX Holdings (5020.TO) is off 16% at Y496 and Cosmo Oil (5007.TO) is down 26% at Y209 after fires broke out at JX Holding's refinery in quake-hit Sendai in Japan 's northeast and at Cosmo Oil's Chiba refinery north of Tokyo . The companies are expected to incur costs associated with maintaining supply and restoring damaged facilities, analysts at Citigroup Global Markets Japan say in a research note. 
With the shutdowns of the nuclear power plants damaged by Friday's massive earthquake in northern Japan, they add operating rates for oil-fired thermal power as a substitute energy source are likely to rise. "We think measures to cope with higher demand for oil as a fuel will be needed," they write.