The same thing happen recently Shell made a takeover offer for BG Group. In Feb 2015, BG Group shares were at their lowest point in 8 years (https://au.finance.

The same thing happen recently Shell made a takeover offer for BG Group. In Feb 2015, BG Group shares were at their lowest point in 8 years (https://au.finance.yahoo.com/echarts?s=BG.L#symbol=BG.L;range=my https://au.finance.yahoo.com/echarts?s=BG.L#symbol=BG.L;rang...). Then Shell makes an offer and the price bumps up. But not enough to make back the losses on the shares in the past 8 years. Shareholders will vote on the offer, and have two choices. 1) Vote No would mean they back SolarCity to increase the share price back to at least where they paid for it. If the No vote is successful, the price instantly loses the gains its made in the past 24 hours, and potentially drops a little further. 2) Vote Yes if shareholders think that the gains they'll get from having Tesla shares (dividend, price gains, cash flow, capital to expand, etc.) will make the SolarCity business a better business/more competitive, etc. There may not be the same doubling/tripling/quadrupling of share price than if they stay a separate company, but it's a much lower risk. Same thing happened for the BG Group/Shell deal. In the end, 99.69% of BG Group and 83% of Shell shareholders approved the takeover. I think we'll see something similar for the SolarCity/Tesla deal as well.