What happened

Electric car stock Tesla (TSLA 12.06%) slipped in early morning trading Wednesday -- not a big loss, but it's down 2% as of 10:15 a.m. ET.

And it's not immediately clear why.

Red arrow going down in front of a hundred dollar bill.

Image source: Getty Images.

So what

Now, there are a few news items that could be affecting the stock -- it's just not entirely clear which is responsible for the falling stock price.

In stock trading news, TheFly.com reported last night that Elon Musk sold another $1 billion worth of his stock holdings in Tesla. That sounds kind of bad, but as TheFly points out, the sales were probably prompted by the Tesla CEO's need to pay taxes on 1.55 million Tesla shares that he bought in exercising stock options.

TheFly also notes that ARK Invest head Cathie Wood sold some 20,400 shares of Tesla on Tuesday, another negative bit of news for Tesla that could be depressing the shares.

Now what

If you ask me, though, the biggest bit of Tesla news today is out of Sweden, where CNBC reports today that local electric car battery manufacturer Northvolt has its Skelleftea battery gigafactory up and running, and "has produced its first lithium-ion battery cell" before the end of the year, as promised and even a bit ahead of schedule.  

Valued at $12 billion, Northvolt isn't exactly in the same league as $1.1 trillion Tesla. Still, it's a sizable company in its own right and a partner to Tesla's electric car rivals BMW, Volkswagen, and Volvo, supplying batteries for their electric cars. With production now underway, Northvolt aims to begin supplying electric car batteries to Tesla's rivals in 2022, ultimately growing production at the Skelleftea plant until it can supply 1 million battery packs per year.

Bottom line: Tesla now has a bona fide battery production rival in Europe, and competition is heating up for the electric car kingpin.