A second major SandRidge Energy (SD +5.6%) investor calls for the company to replace CEO Tom...

A second major SandRidge Energy (SD +5.6%) investor calls for the company to replace CEO Tom Ward and overhaul its board. Mount Kellett Capital, which owns ~4.5% of SD’s shares, says SD "has great assets and should be a great company, but it is clear that it will not be without changes at the top." Shares have been volatile since TPG-Axon criticized SD last week.