Helen Sharkey , 31 , and Gene Foster , 44 , pleaded guilty Tuesday to one count of conspiracy to commit securities fraud .
The two others , former Dynegy executives Helen Christine Sharkey , 31 , and Gene Shannon Foster , 44 , pleaded guilty Tuesday to one count of conspiracy to commit securities fraud .
The Dow Jones industrial average < .DJI > rose 98.74 points , or 1.12 percent , to 8,949.00 .