The issue is EXC's credit rating. To preserve it, EXC has to cut the dividend enough to get its projected free cash shortfall over the next couple years down by at least $2 billion. Cutting the divvy 40% aometime this year gets EXC to that metric. If the divvy is cut AND nat gas rallies to $5.50, the shares will be positioned to rally as that would set the table for future div. increases.
The cut was about preserving the credit rating, and the size of the free cash shortfall over the next two years was a good predictor of it. Once Wall St gets some clarity on EXC's ability to close the free cash shortfall, it will start taking the share price up in anticipation of the credit rating stabilizing. Credit costs are material for utilities, and a credit downgrade would have been far worse for the share price.