What happened

Another day, another new high for Tesla (TSLA -12.34%) stock. Shares of the electric-car maker soared as much as 16.2% on Monday. As of 11:50 a.m. EDT, the stock was up about 12%. This puts shares up more than 600% over the past 12 months and over 300% year to date.

Shares of the growth stock are likely up for a combination of reasons, including building on last week's momentum, speculation that the stock will soon be included in the S&P 500 index, and analyst commentary about the company's upcoming Battery Day event.

Tesla's Model S, X, 3, and Y

Image source: Tesla.

So what

Last week, Tesla shares jumped on news that the stock may soon be included in the S&P 500. This could be fueling further gains on Monday as some investors bet that the stock's inclusion in the index will lead to more demand for the stock.

Now shares may be getting an additional lift from an analyst note saying that the company's Battery Day event on Sept. 22 could be "a major positive catalyst" for Tesla stock. The note comes from Wedbush analyst Daniel Ives, who also believes the automaker could report a fourth quarterly profit in a row. Tesla has repeatedly delayed its battery event, where the company is expected to reveal some news about recent developments in its batteries. But with the date of Tesla's battery event now officially announced in a press release, and given that the event will take place in conjunction with its annual shareholder meeting on the same day, the event seems unlikely to be delayed again.

Now what

Tesla stock's wild run-up has been borderline surreal. The company is now one of the 10 largest companies in the U.S. by market value, with a $325 billion market capitalization.

With such big gains for Tesla stock in the rearview mirror, investors will be watching the company closely when it reports second-quarter results on July 22.