The five largest companies -- Apple, Microsoft, Nvidia, Amazon, and Alphabet -- were worth nearly $15 trillion when Musk first said Tesla could surpass their combined market values. The implied 17-fold return from its current market value of $879 billion means $50,000 invested in Tesla stock today could be worth $850,000 in the future.

Tesla's first-quarter earnings report itself was a disaster, but Musk gave investors some much-needed good news on the conference call.