Cable company Charter Communications (CHTR) - Get Report was up 5.2% in preopen Instinet trading, reversing a downtrend that began Monday following the announced resignation of its CEO Jerry Kent.

This morning, Lehman Brothers added its voice to the general market disapproval of Kent's departure, downgrading the stock to market perform from strong buy and cutting its price target to $17 from $33.

Lehman said Kent's departure and the potential for the company to lose other senior management increases the execution risk for Charter's business plan significantly, especially compared to rivals

Cox

(COX)

and

Comcast

(CMCSK)

.

Lehman also lowered its estimates on the company to reflect "less robust services and advertising growth."

Charter closed down 3.8% Tuesday at $12.22.