NRG Energy shares are surging after the power company announced the resignation of long-time CEO David Crane.

NRG Energy shares are surging after the power company announced the resignation of long-time CEO David Crane.

The company says Crane is stepping down immediately, and he will be replaced by Executive Vice President and Chief Operating Officer Mauricio Gutierrez. Crane has served as CEO since 2003, a year before Gutierrez joined the Princeton, New Jersey-based company.

NRG Energy fell to a 10-year low after the company said Tuesday that it agreed to sell power plants in Pennsylvania and New Jersey. The company also announced third-quarter earnings last month that fell well short of expectations.

The stock is up 7 percent to $11.55 in morning trading. But that share price had fallen 60 percent so far this year, as of Wednesday's close.