Tesla stock fell Thursday, snapping a four-day winning streak.

Shares of the electric- vehicle maker lost 2.2%, closing at $319.11, while the S&P 500 and Dow Jones Industrial Average gained 0.4% and 0.2%, respectively.

One factor that might have sent shares lower was a new law, signed by President Donald Trump on Thursday, that eliminates California's ability to regulate its air emissions. The shift puts at risk Tesla's sales of zero-emissions vehicle credits, which bring in hundreds of millions of dollars each quarter.

Thursday's drop follows a 0.1% gain on Wednesday, the stock's fourth consecutive gain. Shares rose 15% over that span. That left Tesla about $18 lower from levels before a public feud between President Donald Trump and CEO Elon Musk broke out on social media

The feud sent Tesla stock down 17% over two days last week. In a Wednesday post on X, Musk said he regretted some of the things he said about Trump.

The rapid relationship repair let investors focus again on Tesla's robo-taxi launch, scheduled for this month. Musk said Tuesday that June 22 was the target date for the start of service. He added that a Tesla might drive off the assembly line in Austin, Texas, to a customer's home on June 28.

There is still a lot investors don't know about the launch. Points to watch include how many cars will be used initially, how the system will be overseen, what the Tesla ride-hailing app will look like, and if Tesla will invite people to use the network or if it will be open to anyone.

Musk recently said the launch could start with as few as 10 vehicles and that teleoperators would be watching to ensure safety. Some investors have also speculated that early network usage would be by invitation only.

However things begin, investors should have answers to those questions soon. Assuming the launch is successful, investors will want to know how the service will scale up in Austin and other cities across the country.

Coming into Thursday trading, Tesla stock was down about 19% year to date but up about 91% over the past 12 months. Shares were also up about 37% since the company's April 22 first-quarter earnings report, when management reiterated their goal to launch the robo-taxi service in June.

Shares have been all over the place. Most investors know Tesla stock comes with that kind of volatility.