"Market value" is not the current value which is at multi-year lows right now... Hasn't been in this range since after ipo 3.5 years ago.
Solarcity is suppress after NV Energy/PUCN Debacle in January (which is currently being sued, contested). Over the past 3.5 years, Solarcity has grown at a 80% compounded growth rate while reducing all in costs over 1/3 on installing long term revenue generating assets. I think their 12 trailing production is 1.5 terrawatt hours which is bigger then some traditional fossil fuel utilities in our country already. By 2019, they will have a 5 terrawatt hour trailing production and a customer base of 1,000,000 customers with 20 year reoccurring revenues in excess of $1bln/year... And that's at a flat no growth rate from 2016 levels... In just he next three years alone, let alone what will happen over the coming decades.
I feel the "market value" premium is non existent. The deal terms must be negotiated if this is to even come close to making sense for a scty investor.