As its stock price has soared, 's market capitalization has surpassed that of BMW and General Motors. That's gotten the Chinese EV maker more attention, including from CEO Elon Musk.

"420 is ten times better than 42," Musk wrote in a Tweet early morning on Friday, without mentioning any company.

However, it's worth noting that as of Thursday's close, Tesla shares were trading at $438.09, compared to Nio's $42.35.

Twitter users also took the comments as directed at Nio, with the most Liked comment being a photo of Nio chairman and CEO William Li Bin.

Nio stock has outperformed Tesla in the past year.

After surpassing BMW on November 3 with a $35.50 share price and a market cap of $48.2 billion, Nio's stock continued to surge. As of Thursday's close, Nio's stock had surpassed $42 and had a market capitalization of nearly $60 billion, making it the sixth-most valuable auto company in the world.

Nio has yet to enter overseas markets, But in China, it is seen as Tesla's strongest competitor, though Li doesn't admit it.

Nio unveiled its 100kWh battery pack in Beijing today, giving its main selling model, the ES6, an NEDC range of 610km.

At the launch, Li, referring to Tesla, said that Nio is aimed at a different consumer base than Tesla because its average selling price is RMB 150,000 higher than Tesla's in China.

In fact, there is still a big gap between Nio and Tesla in terms of core technology and popularity.

However, Nio's deep roots in the Chinese market, coupled with the fact that the battery swap model is Nio's comparative advantage, makes Tesla feel threatened in China, which may have triggered Musk to post this tweet.