Elon Musk defended his proposed marriage of Tesla Motors and SolarCity Corporation during a second conference call in about 14 hours, assuring investors that his $2.86-billion (R43-billion) plan to combine the companies is a "no brainer" that would benefit both. "This makes Tesla's future execution easier, not harder," said Musk on Wednesday. "It's increasingly unwieldy to work with Solar City at an arm's-length basis."Tesla investors haven't embraced the news. While SolarCity shares rose 15% on Wednesday in trading before US exchanges opened, Tesla fell 11%. Analysts raised concerns about management distraction, the solar company's debt and corporate-governance issues between the two businesses that share the same chairman - Musk, who is also CEO of the electric-car company and largest shareholder of both.Oppenheimer & Co analysts downgraded Tesla to perform from outperform in a research note published on Tuesday, saying they expect "a shareholder fight over this acquisition centred on corporate governance" and a "bailout for SCTY".While it is unusual to announce a proposed acquisition rather than a definitive agreement, Musk's holdings in the two companies required him to keep the market informed.block_quotes_start Tesla customers can drive clean cars and they can use our battery packs to help consume energy more efficiently block_quotes_endCredit Suisse Group AG analysts including Patrick Jobin warned of "many corporate governance challenges"."Investors expect Tesla to keep all its focus on completing the gigafactory and ramping up production of Model 3 in 2018," said Bloomberg analyst Salim Morsy. "Both of these goals are existential for Tesla. A SolarCity acquisition doesn't help execute these critical milestones."But the billionaire was upbeat on Tuesday's conference call. "This is obviously something that should happen," he said.Tesla announced its bid for SolarCity in a blog post, saying the acquisition would "complete the picture". The move comes as Tesla prepares for production of the Model 3, its more affordable electric car, late next year and completes construction of its battery-manufacturing gigafactory east of Reno, Nevada.If the deal is approved, SolarCity would become part of Tesla. It's already part of the family: SolarCity CEO Lyndon Rive and co-founder and chief technology officer Peter Rive are Musk's first cousins. The idea for SolarCity was hatched during a trip the three made to the Burning Man festival in Nevada over a decade ago.story_article_left1According to Tesla, the all-stock deal is worth $26.50 to $28.50 for each SolarCity share. That is a premium of as much as 35% from Tuesday's closing price. The average 12-month price target among analysts surveyed by Bloomberg is $29.82. SolarCity rose 16% to $24.61 and Tesla sank 10% to $196.85 early on Friday New York time."It's clearly not a done deal but rather just an offer for now," said Pavel Molchanov, an analyst at Raymond James. "I think there is room for a deal, but likely at a higher level."With 100.2 million SolarCity shares outstanding, the proposal is worth as much as $2.86-billion. Including net debt, the deal values the company at about $5.7-billion, according to data compiled by Bloomberg.Tesla is being much more generous than other acquirers have been. The bid values SolarCity at about 12.6 times revenue, according to Bloomberg data, while buyers over the past five years have agreed to pay an average of 5.7 times sales for alternative-energy companies. The data looked at deals valued at $100-million or more in areas such as solar and water power.Musk said he would recuse himself from voting on the takeover offer.Tesla shareholders will likely look askance at taking on more debt by combining the money-losing companies, said Morsy."The company just raised $1.4-billion from an equity issuance in May to finance an accelerated production ramp of Model 3," he said. "Investors will have trouble looking past the $3.2-billion in debt that Tesla moves on to its own balance sheet for a SolarCity enterprise value of just $5.8-billion."Musk owns 22% of SolarCity and 21% of Tesla. The two companies work closely together."Tesla customers can drive clean cars and they can use our battery packs to help consume energy more efficiently, but they still need access to the most sustainable energy source: the sun," Musk said in the blog."Most of our customers have an interest in solar," he said on the conference call. "But a small percentage actually have it."..