Japan's reform of its energy market is proving a boon to investors in the company at the center of the Fukushima No. 1 nuclear plant disaster.

Tokyo Electric Power Co.'s shares have surged 59 percent in the six months through Tuesday's close, making it the best performer on the Nikkei 225 Stock Average and the 174-member Bloomberg World Utilities Index.

Tepco, owner of the wrecked plant, is seen as an early beneficiary of government-backed power reform. By April, residential power customers will be able to choose their provider for the first time. And by 2020, utilities will be required to separate their transmission, distribution and retail businesses.