A year after Tesla CEO Elon Musk joked about how he had secured funding to take his company private a $420 per share, Tesla stocks have now actually hit that milestone pricing. Tesla stock prices hit an all-time high, pun intended, of $422.01 on Monday, closing at $419.22 per share. The 3 percent surge in the stock price sent the company's market capitalization to more than $75 billion.

The number "420" is typically associated with the use of Marijuana. The origin of the reference is unclear, but the number is reportedly associated with the California Senate Bill 420, which covers the use of medical marijuana.

After Tesla's stocks hit the $420-mark, Musk immediately posted a comment on Twitter saying how the stock was now "so high." Musk is no stranger to the drug as he is known to be an occasional pot user. Musk famously went on a podcast and smoked marijuana live during the broadcast. 

Musk's original "420" joke on Twitter back in August of last year foreshadowed the prices on Monday. However, getting to the $420-mark was not a smooth ride as the company's stocks essentially went through a rollercoaster ride over the past year.

Shortly after Musk posted his now infamous claim back in August, Tesla saw its stock plummet to a three-year low of just $179 per share. The stock dipped below the $200 mark in late May, after Morgan Stanley analysts cut the company's worst-forecast from $97 to $10 per share. The investment bank claimed that its forecast was based on concerns over Tesla's rising debt and its geopolitical exposure.

Analysts from other banks, including Goldman Sachs, also cut their forecasts citing concerns over the demand for the company's products. Tesla stock prices reached its lowest point in June when it hit $178.97 per share. During this time, Tesla was facing issues on multiple fronts, including litigation, government inquiries, massive layoffs, and production challenges.

Musk was also sued by the Securities and Exchanges Commission for securities fraud. The SEC's suit was aimed at banning the executive from holding a position with Tesla and his other publicly traded companies. Musk managed to keep his CEO role with Tesla through a $20 million settlement with the agency.

During the final months of 2019, Tesla managed to turn things around. The company reported a surprisingly profitable third quarter this year. This sent Tesla's stocks rebounding following the better-than-expected earnings.

After Tesla announced that its new factory in Shanghai, China was to be completed ahead of schedule, the company saw its stocks surge by more than 20 percent. The company's new Shanghai Gigafactory is its first major facility outside of the United States. The facility is expected to allow Tesla to further tap into the Chinese market.