What happened

Thursday was a fairly eventful news day for bellwether electric vehicle company Tesla (TSLA 2.92%). On balance, the latest developments were taken positively by investors. They traded the company's shares up marginally, as the S&P 500 index booked a 0.6% decline.

So what

Arguably the most stock-moving news item of the day -- aside from the latest developments around CEO Elon Musk's pursuit of Twitter, which don't directly affect Tesla -- came from Europe. The institutions that run the 27-member state EU have reached a deal to mandate all carmakers reach a zero-emission target starting in 2035.

This means that all autos sold in the vast economic bloc will have to be non-internal combustion models. At the moment, that largely means electric vehicles (EVs) such as the sleek models offered by Tesla.

Concurrently, citing research from Jato Dynamics, Bloomberg reported that the company's Model Y was the best-selling car in Europe last month. All told, Tesla delivered more than 29,000 Model Ys in September, tripling its tally from the same month of 2021. That figure also trounced that of the No. 2 model, the Peugot 208, with roughly 19,600.

Now what

In rather less encouraging news, a Wall Street Journal report published Thursday said that the Justice Department and its Securities and Exchange Commission are investigating Tesla.

Citing "a person familiar with the matter," the newspaper said that both arms of the government are trying to determine whether the company misled investors and consumers about the Autopilot system packed into its vehicles. Despite its name, the system offers extremely limited automated functionality; it's actually more of an assisted-driving solution.