New York (CNN Business) Tesla CEO Elon Musk once said he had a buyer that would take Tesla private at $420 a share. That never happened -- but the stock just got there on its own.

Musk tweeted in August last year that he is "considering taking Tesla private at $420. Funding secured." At the time, the share price was $379.57 -- nowhere near $420. Speculation about the identity of the mystery buyer was rife, and many investors thought Musk might be making a joke: 420 has become synonymous with cannabis culture.

That reference was not lost on Musk -- and he joked about it Monday.

Whoa ... the stock is so high lol — Elon Musk (@elonmusk) December 23, 2019

His tweets landed Musk in hot water with the Securities and Exchange Commission , as well as with investors . The SEC found Musk's tweets had misled shareholders: He never actually secured the funding to take the company private.