S&P initiates coverage of Tesla with 'sell' rating

Standard & Poor's initiated coverage of Tesla Motors Inc with a "sell" rating, citing caution over the electric carmaker's stock price.

"We are positive on Tesla's fundamental growth story, but are concerned by its valuation," S&P analyst Efraim Levy said in a research note.

"We believe there is execution risk for Tesla as well as opportunity. We expect these volatile shares to be impacted by news flow and investor sentiment shifts," he added.

S&P set a 12-month target share price for Tesla of $150. The stock was off 0.3 percent at $183.42 in afternoon trading on Wednesday on the New York Stock Exchange.

Also on Wednesday, Barclays analyst Brian Johnson said in a research note that Tesla's third-quarter sales will likely top the company's forecast, but he still sees $141 a share as "fair value."

On Tuesday, Wedbush Securities analyst Craig Irwin raised his rating on Tesla to "outperform" from "neutral" and raised his target share price to $240 from $180. He cited a proprietary survey that supports higher expectations for the company's next generation of smaller, more affordable electric cars, dubbed Gen III.

(Reporting by Ben Klayman; Editing by Leslie Adler)