Cathie Wood’s stunning new $2,600 Tesla prophecy and Wall Street’s Nvidia stock prediction share an often overlooked investing truth

On June 13, I posted a story asserting that the giant run-up in its market cap to $3.1 trillion made it virtually impossible for Nvidia to grow its sales and profits at the lightning pace needed to reward shareholders.

The same day, Cathie Wood, chief of Ark Invest, appeared on CNBC to champion her firm's new, breathtakingly bold, projections for Tesla's stock price. Wood posited that the EV leader's shares would hit $2,600 by 2029, almost fifteen-fold its current level of $175. In a report issued the previous day, three Ark analysts provided the financial metrics it expects Tesla to reach five years hence that justify that never-before-witnessed moonshot in value. Their work mightily impressed Tesla CEO Elon Musk, who tweeted, "I think it's worth looking at Ark's analysis, I think that's the most accurate analysis."

Stacking Nvidia's challenges versus Wood's stunning new Tesla prophesy

Comparing the heroics Nvidia must achieve to prove a good investment, and the feats Wood expects from Tesla, makes her forecast look like the bigger fantasy

In the Nvidia piece, I stated that to deliver its shareholders a relatively modest 10% annual return over the next seven years, Nvidia would most likely need to double its market cap to $6.2 trillion by 2031. I'll spare you the details, but I estimated that getting there would require, by the end of that timeframe, $200 billion in annual net earnings and $580 billion in revenues, for respective annual increases of 25% and 50%. Conclusion: The chances of dwarfing the numbers now posted by the likes of Apple, Microsoft and Alphabet are remote, to put it mildly. Put simply, investors have hiked the bar for what the AI-pioneer must achieve so high that it's most likely to prove a great company and a poor investment.

The Ark report predicts that Tesla will achieve an "enterprise value" of $8.2 trillion in five years. Although enterprise value includes debt as well as equity, Ark appears to attribute almost all of that number to the latter. Hence, it's saying that Tesla's market cap will jump one-third higher than the required but fantastical $6.2 billion bogey for Nvidia in my "roadmap for success," and do it far faster, in five years instead of seven! Tesla starts the contest sandbagged by a heavy handicap: It's earned just $13.7 billion the last four quarters, one third the $42.6 billion booked by Nvidia.

The Ark analysis puts Tesla profits by 2031 in the $300 billion range. Getting there would require annual gains of 90% through 2029. That's almost four times the hurdle for Nvidia. Ark foresees $1.2 trillion in revenues for Tesla at the end of the five year window; ringing the bell would take annual increases of 65%, a growth rate far faster than the 50% needed to make Nvidia a decent buy at these prices.

Based purely on the scale of the numbers measured against what other tech greats have garnered and the size of Tesla's industry, the Ark estimates look far more outrageous than the over-the-top numbers baked into Nvidia's valuation. That $300 billion in 2029 profits would be three times what Apple earns today, and the $1.2 trillion in revenues would tower at five-times Microsoft's. Tesla's 2029 sales would equal the combined total for the world's five largest automakers, Volkswagen, Toyota, GM, Ford and BMW. At an $8.2 trillion market cap, Tesla would be worth four-fold the all-in valuation of the global auto industry.

The goals investors have set for Nvidia, and Wood's stupendous outlook for Tesla, turn on the vision that a single player will dominate a revolutionary industry, facing little competition, virtually in perpetuity. For AI colossus Nvidia, that domain's already exploding, what's in doubt is the prospect of dominance forever. For Tesla, the business—robo taxis running on its super-lucrative software—doesn't exist yet, and whether and when it arrives, how profitable it will be, and whether King Elon can rule it alone, are all big questions.

You've got to marvel at Wood for making a call that looks ridiculous based on anything we've ever witnessed in the financial markets, and Musk for praising the "analysis" behind the gravity-defying target. They might be true believers—but investors should do the math.

This story was originally featured on Fortune.com