Comcast (CMCSA, Financials) shares jumped after the company said it will split its media and technology businesses into two publicly traded companies.

The plan will separate NBCUniversal and Sky from Comcast through a tax-free spin-off. Comcast shareholders will own shares in both companies after the deal closes, which is expected in about a year.

Mike Cavanagh will become CEO of NBCUniversal. Michael Angelakis, Comcast's former chief financial officer, will become CEO of Comcast.

The move comes after a difficult year for Comcast shares and a tough stretch for traditional media. Cable TV keeps losing ground to streaming, while companies across the sector are trying to get bigger or more focused.

For Comcast, the split gives each business a cleaner story. Comcast can focus on connectivity, while NBCUniversal and Sky can compete more directly in media and entertainment.

Investors liked the idea. Comcast shares rose sharply in premarket trading after the announcement.