Sempra stock re-energized

Shares of Sempra Energy made their biggest gain in 26 years after two activist investors said the San Diego-based gas and electricity provider should consider big changes to its business.

Elliott Management and Bluescape Resources said Sempra should add six new independent directors to its board and have a committee review its strategy.

The two firms say they own 4.9 percent of Sempra’s stock. While Sempra owns several businesses that are performing well, the investors say it’s become a conglomerate with parts that don’t fit together strategically or financially.

The company bought a majority stake in Texan power transmitter Oncor for $9.45 billion in March and its CEO recently stepped down.

The stock surged 15.5 percent Monday, its biggest gain since April 1992.