NRG Energy Inc. said Tuesday it will pay $12 a share or $2.8 billion in cash for Vivint Smart Home Inc. and assume $2.4 billion of the company's debt for a total deal value of $5.2 billion. The price of $12 a share is a 33% premium to Vivint's closing share price on Monday. Shares of Vivant jumped 31% in premarket trades. The deal is expected to close in the first quarter. NRG said the transaction will fit its effort to become "the leading provider of essential services for homes and businesses.