Tesla (TSLA) shares plummeted Monday, making them the biggest S&P 500 decliner and starting the week on a negative note as the electric vehicle maker's stock has declined in 澳洲幸运5官方开奖结果体彩网:each of the last seven weeks.

The shares have lost more than half of their value since a Dec. 17 record close of $479.86 as Tesla stock has given back all of its post-election gains since President Donald Trump's win in November. Since Trump took office and 澳洲幸运5官方开奖结果体彩网:Tesla CEO Elon Musk started working in the 澳洲幸运5官方开奖结果体彩网:cost-cutting Department of Gove𓃲r♏nment Efficiency, however, shares have tumbled.

The stock finished down more than 15% to just over $222, its lowest level since late last year, pulling the company's market capitalization to around $840 billion, according to Visible Alpha data. Equity markets were down broadly 澳洲幸运5官方开奖结果体彩网:in today's trading.

Tesla has been pressured by a weak fourth-quarter 澳洲幸运5官方开奖结果体彩网:deliveries and 澳洲幸运5官方开奖结果体彩网:earnings reports, uncertainty around 澳洲幸运5官方开奖结果体彩网:Trump's tariffs, and declining 澳洲幸运5官方开奖结果体彩网:sales in China and 澳洲幸运5官方开奖结果体彩网:registra𒆙tions in Europe to start the year. Some investors and analysts are divided over whether Musk's involvement with the Trump administration could 澳洲幸运5官方开奖结果体彩网:hurt Tesla's brand and sales.

Analysts remain divided on the stock, with the 19 brokers tracked by Visible Alpha split between 10 "buy," five "hold," and four "sell" ratings.

UBS analysts on Monday maintained their "sell" rating and lowered their price target to $225 from $259, and cut their estimates for first-quarter deliveries to 367,000 from 437,000 previously. They said the new Model Y and a yet-to-be-announced lower cost model will likely help sales, but see demand for the new Model Y as "somewhat muted" so far, and expect a lower-cost vehicle to come with a lower margin.

This article has been updated to reflect the latest share-price information.