Comcast is moving forward with plans to spin off its NBCUniversal cable television networks including MSNBC and CNBC, sources say, shedding a once core part of the business that has been a casualty of the streaming video revolution.

The new entity, which is tentatively called "SpinCo," will be led by NBCUniversal Chairperson Mark Lazarus. Anand Kini, the CFO of NBCUniversal, will be its financial and operating head. During Comcast's Q3 investor call, President Michael Cavanagh said there could be an opportunity to play some offense with this move.

Comcast is spinning off many of NBCUniversal’s cable television networks, including USA Network, CNBC and MSNBC, into a separate public company