Tesla co-founder and CEO Elon Musk gestures while introducing the newly unveiled all-electric battery-powered Tesla Cybertruck at Tesla Design Center in Hawthorne, California on November 21, 2019. FREDERIC J. BROWN | AFP | Getty Images

Tesla stock reached an all-time high of $422.01 before closing Monday at $419.22, up more than 3% and bringing Tesla's market cap to more than $75 billion. The stock surpassed $420 more than a year after CEO Elon Musk tweeted he had "funding secured" to take the company private at that share price. The now-infamous Aug. 7, 2018, tweet sent the stock soaring, but it also marked the beginning of a chaotic ride for both the company and Musk. In the 16 months that followed, Tesla stock bottomed out at a three-year low just under $177 per share in June before boomeranging back up and breaching $420 on Monday. 420 Tweet. Musk marked the occasion with a joke. Musk tweet. The road to $420 wound through new performance records as well as extreme low points that have brought litigation, government inquiries, layoffs and operational challenges. That journey was capped off by a surprisingly profitable third quarter and a so far stellar end of the year. In the aftermath of the original tweet, Musk announced that Tesla would remain a publicly traded company, but that wasn't enough to calm investors' nerves. Tesla stock dropped about 16% over the three weeks following the tweet. Musk was quick to stun investors again when he appeared just weeks later on the Joe Rogan podcast and smoked what appeared to be marijuana during a wide-ranging interview. The antic drove the stock down another 6.3% the next day and sparked calls for his resignation and questions about his mental stability. The SEC then sued Musk for securities fraud because he failed to disclose the proper documents before announcing the intent to take Tesla private. The SEC sought to ban Musk from holding officer or director positions at any publicly traded company. Musk held onto his role as CEO by settling with the SEC, though he was forced to relinquish his role as chairman and pay a $20 million fine.

"This unjustified action by the SEC leaves me deeply saddened and disappointed," Musk said at the time in a statement to CNBC. "I have always taken action in the best interests of truth, transparency and investors. Integrity is the most important value in my life and the facts will show I never compromised this in any way." After the settlement, Tesla shares jumped 17.35% to $310.70, but the stock turned south again days later when Musk mocked the SEC in a tweet, calling the agency the "Shortseller Enrichment Commission." Shares closed the following day down 7% at $261.95 per share. SEC tweet. The company recovered a bit when it reported a surprisingly profitable third quarter of 2018. The report showed better-than-expected car sales and a faster timeline on its Model 3 production, sending stock soaring more than 12%. Musk described it as an "incredibly historic quarter." The celebration was short-lived. In the fourth quarter, Tesla announced it would cut 7% of its workforce and Musk wrote in an email to employees that the company faces a "very difficult" road ahead. The January layoffs affected at least 1,000 California employees and sent the stock down 13%. When Tesla reported a profitable fourth quarter the same month as layoffs, it wasn't enough to satisfy Wall Street, and the stock took a 5% hit.

Stock falls below $200

Tesla stock dipped below $200 a share in late May as Morgan Stanley auto analyst Adam Jonas cut the firm's worst-case forecast on Tesla's stock from $97 a share to just $10, citing concerns about the company's increased debt load and geopolitical exposure. Other major analysts followed suit, including Goldman Sachs, which slashed its price target a month later on concerns about demand for Tesla vehicles. UBS' Colin Langan also cut his price target by 20% in June to $160 a share and reiterated his sell rating. The concerns followed several changes to Tesla's business plans, including an announcement to shift to an online sales model that would result in many store closings and price cuts. The stock spiraled to its lowest point in three years on June 3 at $178.97 per share.

Third-quarter comeback