Tesla (TSLA.O) shares have considerably dropped last Monday due to a downgrade from Goldman Sachs. This brought the car manufacturer to a total decline of 11 percent since the quarterly report was issued last week.

The Reasons Behind Tesla Stocks Decrease

One of the reported factors to this sudden decline was that the company will be spending a lot on the pre-launching campaign of the "Model 3" due to the possibility of a delayed release in the market. With this, David Tamberrino, an analyst from Goldman Sachs, has decided to downgrade the status of Tesla from "neutral" to "sell."

According to Reuters, this had then resulted to another 4.83 percent stock decline. Last Monday, Tesla stocks are reported to be $244.52. If ever the trend will continue, then this will be the worst three-day performance of the company's shares since June 2016.

Before the drop happened, Tesla was experiencing a surprising surge of more than 30 percent last December. And by the start of the year, it kicked into a 14 percent increase.

Increased Competition In The EV Industry

Tamberrino said that if the current trend continues, Tesla's stock priced would be declining at an alarming rate. Another reason to this unexpected stock decrease is that Tesla's investors are not any more sure whether the company will compete effectively with General Motors Co (GM.N), knowing that the latter will also be releasing its own set of electric vehicles.

According to CNN Money, the acquisition of SolarCity by Tesla is another big factor in the company stocks' decrease in value. Tamberrino said that Tesla should instead focus on manufacturing vehicles, instead of diverting its attention to other industries and interests.

Tamberrino later added that it is very unlikely for Tesla to sell more than 100,000 "Model 3" units by the middle of 2018.