Capping a wild day on Wall Street in which Pacific Gas and Electric Co. stock crashed and soared as investors weighed the prospect of government aid, California’s top utility regulator said Thursday his agency can help the utility avoid financial catastrophe because of the state’s raging wildfires. Michael Picker, president of the California Public Utilities Commission, said his agency does not want PG&E and the state’s other investor-owned utilities to file for bankruptcy. In a move he conceded was unusual, he briefed investors and analysts on his views before issuing a public statement Thursday, a decision that may have contributed...